VACC Austria DokuWiki - User contributions [en]

LOWS

2009-03-21T07:22:51Z

Michael Rohrwasser:

LOWS is the ICAO code of [[Salzburg]] airport.
You may also visit the real world website of [http://engl.salzburg-airport.com/ Salzburg Airport - W.A. Mozart].

VFR

2009-03-21T07:16:56Z

Michael Rohrwasser: Die Seite wurde neu angelegt: [http://en.wikipedia.org/wiki/Visual_flight_rules VFR (Visual Flight Rules)]

[http://en.wikipedia.org/wiki/Visual_flight_rules VFR (Visual Flight Rules)]

Study Guide:Tower

2008-07-30T19:02:43Z

Michael Rohrwasser: /* Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen */

'''This study guide is still work in progress. Stay tuned for further chapters.
'''
==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are opposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="left">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="left">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearance (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you, continue
approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach, wind 140
degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline, presently at
your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through your airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expect runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Separation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-12T15:38:29Z

Michael Rohrwasser: /* Arriving Traffic */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are opposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="left">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="left">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearance (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you, continue
approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach, wind 140
degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline, presently at
your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through your airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expect runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:47:28Z

Michael Rohrwasser: /* VFR Traffic - Differences */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are opposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearance (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through your airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expect runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:46:08Z

Michael Rohrwasser: /* VFR Traffic - Differences */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are opposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearance (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through your airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:25:25Z

Michael Rohrwasser: /* Opposite runway operations */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are opposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearance (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:22:07Z

Michael Rohrwasser: /* Use of the word takeoff */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearance (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:21:33Z

Michael Rohrwasser: /* Working Ground Positions */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearance''' 
Start-up clearance can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearance''' 
Push-back clearance can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:20:40Z

Michael Rohrwasser: /* Issuing IFR Routing Clearances */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearance:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:20:08Z

Michael Rohrwasser: /* Working Delivery Positions */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-08T16:19:30Z

Michael Rohrwasser: /* Radio Communication - Basics */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because communication is crucially important for Air Traffic Control a fixed format and syntax is used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
===Producing Lift===
For an aircraft to fly the lift force produced by (mostly) the wings has to outweigh the gravitational force that affects the aircraft.

Basically a wing produces lift by deflecting the air it moves through into one direction. According to Newton's third law of motion the lift is produced into the opposite direction. This lift grows with the speed the aircraft has in relation to the air and with the angle the wing draws with the direction of movement. This angle is called Angle of Attack (AoA). [[Bild:Angle_of_attack.png|framed|Angle of Attack]]

The principle only works as long as a steady airflow around the wing exists. As soon as the airflow seperates from the wings surface the lift starts to decerease. The AoA at which this occurs is called critical Angle of Attack. It depends on the profile of the wing and it's dimensions but for subsonic aircrafts it typically lies between 8 and 21 degrees.

Think of an level flying aircraft that reduces it speed. In order to compensate the reducing lift the pilot has to raise the nose. However at some point the Angle of Attack will cross the critical angle of Attack and the pilot will find himself in a stall. So the speed of an aircraft is limited on the lower side by the so called stall speed. Because the stall speed depends on the profile most aircraft are equipped with devices that alter the profile during flight such as flaps or slats.

On approach pilots have to fly in a certain speed range in order to conduct a safe landing. The lower boundary is called landing reference speed and is often a fixed multiple of the stall speed. As a result of this the approach speed also depends on weight an aircraft configuration (Flap/Slat setting). For safety the Approach Vapp is higher than Vref and the difference depends mostly on the weather conditions.

Generally you can say that bigger aircraft also have a bigger approach speed however at some point this rule does not work anymore because the Vref depends largely on the aircrafts weight in relation to it's maximum takeoff weight (MTOW). The speed ranges from 50 knots in a C150 up to 170 knots with a fully loaded 747. However for example it is possible that a light 747 is slower than a fully loaded 737.
===Aircraft Categories===
The most important ways of categorizing aircraft in aviation are by weight or by approach speed.
====Weight Categories====
Aircraft are categorized into three weight categories:
{| class="prettytable"
|'''Category'''||'''MTOW'''
|-
|Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}
Weight depicted is MTOW.
====Approach Speed====
Aircraft are categorized by their reference approach speed (Vref) at maximum landing weight:
{| class="prettytable"
|'''Category'''||'''Vref'''
|-
|A||<= 90 knots
|-
|B||91 - 120 knots
|-
|C||121 - 140 knots
|-
|D||141 - 165 knots
|-
|E||>= 165 knots
|}

==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Radar

2008-07-05T17:30:15Z

Michael Rohrwasser: /* Holding */

==Responsibilities==
The responsibilities of a Radar Controller is to maintain the required seperation between aircrafts all the time by using different techniques of sequencing.

==Airspace Structure==
LOWW is located very close to the Austrian state boundaries with Hungary, Slovakia and the Czech Republik and space within the TMA (Terminal Maneuvering Area) is very limited. 
Arrivals are being transferred to LOWW_APP by '''five independently working ACC sectors''' (LKAA/ACC Praha, LZBB/ACC Bratislava, LHCC/ACC Budapest, ACC Wien South, ACC Wien North). Therefore final decisions on the arrival sequence are normally made at a distance of approximately 40 NM from touchdown. 
 
LOWW_APP itself operates '''up to four different sectors''', depending on the amount of traffic. Two '''Upper Radar''' sectors specify the arrival sequence for the Lower Sectors. Upper Sectors are operated between FL240 and FL110. 
 The '''Lower Radar''' (FL100 and below) will then make final decisions on the arrival sequence by transferring arriving aircraft to the '''Director''', who issues vectors onto the final approach track and sets up a safe flow of landing traffic. Unless otherwise instructed, initial contact on Director frequency (normally 119.800) shall be made by stating the callsign only in order to reduce frequency load. 
 
When the appropriate spacing is assured until touchdown, Director will transfer the arriving aircraft to Tower. 

==Minimum Radar Separation==
A Controller has to make sure that two Aircraft which are under his control never get closer than the minimum radar seperation. If two aircraft get closer than that, this incident is called a conflict.
*The standard Minimum Vertical Seperation is 1000 ft up to FL290 and 2000 ft above that. However Austria is considered RVSM (Reduced Vertical Seperation Minima) airspace so the upper limit of the 1000 ft seperation minimum is raised to FL410. In real life this demands special equipment of the aircraft involved, however on VATSIM all aircraft are considered RVSM capable.
*The Minimum Horizontal Seperation depends on the radar equipment involved. APP Sectors work with a minimum of 3 nm, CTR Sectors use 5 nm.

There are some cases where these minima may be under-run such as visual seperation or formation flights.

==MRVA, MSA, MOCA==
MRVA (Minimum Radar Vectoring Altitude): The MRVA is defined as the lowest available altitude above Mean Sea Level (MSL) in controlled airspace under consideration of the MSA (Minimum Safe/Sector Altitude) above ground and the airspace structure within a specified area.

MSA (Minimum Safe/Sector Altitude): Minimum Sector Altitude is the minimum altitude that may be used under emergency conditions which will provide a minimum clearance of 1000ft above obstacles and terrain contained within a sector of 25 NM radius centred on a radio navigational aid. MSA can be given as areas between radials from a VOR at the airport.

MOCA (Minimum Obstacle Clearance Altitude): This is the lowest altitude that an aircraft can fly in IMC (Instrument Meteorological Conditions) and still keep safe clearance from terrain and obstacles. MOCA is often lower then MEA (se below). It is only used in emergencies, especially to get below icing.

==Structure of Flightplans and Routings==
===SIDs===
SID (Standard Instrument Departure): It is a pre-defined route which aircrafts have to fly to get to their initial airway to follow their desired routing to their destination.

e.g.: Flightplan from LOWW (Wien) to Salzburg (LOWS): SITNI L856 SBG DCT - SITNI is our first waypoint of our routing and let us say for instance that in Vienna Runway 29 is in use. We take a look at our charts and we see that we can plan for a socalled SITNI4C departure route.

SIDs are specified by the local Air Traffic Control. A SID can contain the following navigation aids: R-NAV Waypoints, VORs, NDBs, etc.

===STARs===
STARs (Standart Terminal Arrival Routes): STARs are pre-defined routes to get an aircraft to the airport.

A STAR falls into three parts namely navigational point, version number and runway (depending on the airport), e.g. GAMLI4W arrival. The point at which the STAR ends is called Initial Approach Fix (IAF). In some cases the STARs continue and end at the Final Approach Fix (FAF), and that means that you as controller don't need to vector the aircraft unless there is other traffic in the way. The only thing you have to do is to instruct the pilot how to descend the aircraft.

There are exceptions of course, where the STARs don't end at the final, but at a navigational point some distance away from the runway. You as a controller must give vectors the last part to the runway. If you for some reason don’t give vectors, the pilot must enter holding at the STAR's ending point (clearance limit).

===Types of Instrument Approaches===
An '''instrument approach''' or '''instrument approach procedure (IAP)''' is a type of air navigation that allows pilots to land an aircraft in reduced visibility (Instrument Meteorological Conditions [IMC]) or to reach visual conditions permitting a visual landing.

There are 2 types of approaches:

* Precision Approaches
* Non-Precision Approaches

1.) '''Precision Approaches'''

- ILS (Instrument Landing System)
- MLS (Microwave Landing System)
- PAR (Precision Approach Radar)
- GPS (Global Positioning System)
- LAAS (Ground Based Augmentation System [GBAS] for Global Satellite Navigation Systems [GNSS])
- JPALS (Joint Precision Approach and Landing System)
- GCA (Ground Controlled Approach)

2.) '''Non-Precision Approaches'''

- Localizer
- VOR
- NDB (with ADF)
- Localizer Type Directional Aid (LDA)
- Simplified Directional Facility (SDF)
- GPS (Global Positioning System)
- TACAN
- Surveillance Radar Approach (SRA) [also known in some countries as ASR approach]
- Visual

==Basic Instructions==
===Vectoring===
There are 2 types of vectoring:
* Lateral Vectoring
* Vertical Vectoring
====Lateral Vectoring====
ABC123, turn left heading 165°
DEF243, turn right heading 300°

When issuing a heading to an aircraft, make sure that you are using a direction ending on 0 (zero) or on 5 (five).

If you provide Radar Vectors to an aircraft then always tell the pilot the reason why you are doing this:

ABC123 turn right heading 080°, radar vectors for ILS approach RWY 11
After vectoring an aircraft you might have to send the aircraft back on its flight planned route:
ABC123, proceed direct to SITNI
It is important to know, that as soon as you take an aircraft of a publsihed route, either by vectoring or by using a direct, you are also responsible for the necessary terrain clearance. To do this always consider the MRVA on the aircrafts path.
====Vertical Vectoring====
ABC123, climb FL240"
DEF243, descend Altitude 3000 feet, QNH 1016"

As you can see there are 2 types of heights namely Altitude and Flightlevel (FL).

'''Flightlevel''' is used for aircraft flying above the Transition Altitude, Transition Level or climbing through and above the Transition Layer (Altimeter in the aircraft is set to Standard Pressure [1013 QNE]).

'''Altitude''' is used for aircraft flying below the Transition Altitude or for Aircraft descending through and below the Transition Layer (Altimeter in the aircraft is set to local QNH).
====Speed Control====
A controller may issue speed instructions within an aircrafts operating limits. There are two possible ways to do this, either by using Indicated Airspeed (FL280 or below) or by specifying a Mach number (FL280 or above).
ABC123, maintain speed 280 knots
DEF456, maintain Mach 0.81

==Seperation and Sequencing Techniques==
===Planning===
LOWW_APP is aiming at a maximum of 15 minutes flight extension for sequencing of arrivals to LOWW within the TMA (Terminal Maneuvering Area). Arriving aircraft will normally get radar vectors to '''one common downwind'''. 

===The Delay Vector===

===Speed Control===
For efficient sequencing and spacing of arriving aircraft Radar will instruct specific indicated airspeeds to be maintained (speed control). Aircrews are expected to maintain instructed speeds as accurately as possible (+ / - 10knts). In case of unability to maintain instructed speed (weather reasons, operating limitations etc.) ATC has to be informed immediately. 

===Holding===
'''Useage''' 
The primary use of a holding is delaying aircraft that have arrived over their destination but cannot land yet because of traffic congestion, poor weather, or unavailability of the runway. Several aircraft may fly the same holding pattern at the same time, separated vertically by 1,000 feet or more.

'''Flying a Hold''' 
Most aircraft have a specific holding speed published by the manufacturer.Maximum holding speeds are established in order to keep aircraft within the protected holding area during their one-minute inbound and outbound legs.

As a rule of thumb the Speed to be flown depends on the altitude or flight level the aircraft is at within the hold as follows:

* At 6,000' MSL and below: 200 knots
* From 6,001' to FL 140: 230 knots
* At and above FL140: 265 knots

* '''Duration'''
A Complete hold should take:

* FL140 and below 4 minutes
* FL140 and above 5 minutes

* '''Holding Clearance'''
A holding clearance issued by ATC includes at least:
- A clearance to the holding fix.
- The direction to hold from the holding fix.
- A specified radial, course, or inbound track.
- If DME is used, the DME distances at which the fix end and outbound end turns are to be
commenced.
- The altitude or FL to be maintained.
- The time to expect further clearance or an approach clearance.
- The time to leave the fix in the event of a communications failure.

* '''Standart Holding Pattern'''

* Standard Hold: A hold where all turns are made to the right
* Non Standard Hold: A hold where all turns are made to the left
* Holding Course: The course flown on the inbound leg to the holding fix.
* Inbound Leg: The standard 1 or 1.5 minute leg to the holding fix as Published
* Holding Fix: This can be a VOR, a VORDME, an Intersection or an NDB
* Outbound Turn: A standard rate, 180 degrees turn which is begun at the holding Fix.
* Abeam: The position opposite the holding fix, where the outbound begins.
* Outbound Leg: This leg is defined by the inbound leg, pilots should adjust the outbound leg
so that the inbound turn, the other standard 180° turn is completed just as the holding
course is intercepted.
* Holding Side: The side of the course where the hold is accomplished.
* Non Holding Side: The side of the course where you do not want the pilot to be holding

* '''Non Standart Holding Pattern'''

A non-standard holding pattern is one in which
- The fix end and outbound end turns are to the left; and/or
- The planned time along the inbound track is other than the standard one-minute or
one-and-a-half minute leg appropriate for the altitude flown.

* '''Entry Holding Procedure'''
**Direct Entry (aircraft flies directly to the holding fix, and immediately begins the first turn outbound)
**Parallel Entry (aircraft flies to the holding fix, parallels the inbound course for one minute outbound, and then turns back, flies directly to the fix, and proceeds in the hold from there
**Teardrop Entry or Offset Entry (aircraft flies to the holding fix, turns into the protected area, flies for one minute, and then turns back inbound, proceeds to the fix and continues from there).

===Coordination with adjacent Sectors===
The coordination respectively the communication between controllers (and of course pilots) is on of the most important things in aviation.

A clear instruction to the person I want to speak to falls into 4 parts:

- Who am I calling
- What do I want
- How are we going to archieve this (short and clear instructions!)
- Did the person I called unterstand my instruction properly

==VFR Traffic==
===Flight Information Positions===

Flight Information Service (FIS) is an air traffic facility that provides a myriad of services to the pilot, such as pilot briefings, relaying of clearances and broadcasting of weather information.
At selected locations, FIS also provides en-route Flight Advisory Services.

===Information Positions===

* Traffic Information
* Weather Information
* Special Requests

LOWW_I_APP (118.520) and LOVV_I_CTR (124.400) are the 2 FIS Positions within Austrian airspace. They are responsible for the VFR Flights. They allocate Squawks, provide Traffic Information and offer Weather Information (worldwide) and coordinate with other controllers requests from pilots.

==Abnormal Situations - Emergencies, Radio Failures==

''' Emergencies'''

Emergencies are very uncomfortable situations for every controller. Emergencies shall be handeled expeditiously to get them safe down to the ground.

'''Note:''' The pilot tells the ATC what his intentions are and what he will do next and not the other way round. ATC keeps all the traffic in the vicinity of the emergency aircraft away to assure that no other aircraft gets injured.

'''All Weather Operations (AWO)''' 
With Low Visibility Procedures in operation, standard approach runway will be runway 16. 
Arrivals will be vectored out of the holdings into the '''left hand circuit''' for runway 16. Approximate track distance from the holdings to touchdown shall be calculated with '''40 to 70 nautical miles'''. 

==Controlling CTR Positions==
Area Control Center (ACC) provides ATC to aircraft on the en-route phase of flight.
This includes giving information that the pilot needs such as weather and traffic information. The ACC controller has to assure that the seperation is always appropriate regarding to the traffic in the vicinity ( 5 nautical miles lateral, 1000 feet vertical at least ).

ACC is also responsible for all airports where Tower and Approach are not manned. If you are working on the ACC position always remember that this position is a demanding position and requires great knowledge and experience.

[[Category:Dokumentation]]

Example Flight

2008-07-05T17:23:29Z

Michael Rohrwasser: /* Flugplan */

== Beispielflug für neue Piloten ==

=== Einleitung ===
Dieser Flug, den wir Schritt für Schritt gemeinsam durchgehen wollen, soll dir einen ersten Auszug aus der Faszination der virtuellen Fliegerei
im [[VATSIM]] Netzwerk geben. Wenn du dich an diesem Tutorial orientierst kann eigentlich nichts schief gehen. Es wäre sehr
empfehlenswert dir einen
Termin mit deinem Mentor zu vereinbaren, damit ihr dieses Tutorial gemeinsam durcharbeiten könnt (z.B. über [[TeamSpeak]],
[[Skype]], etc.). Falls du
der Meinung bist, dass du das auch alleine packst können wir jetzt beginnen. Dein erster Flug wird von Wien nach Salzburg
führen.

=== Benötigte Software ===
Bevor es an die eigentliche Flugvorbereitung geht, sollten wir besprechen welche Software du verwendest bzw. welche Programme du benötigst.
==== Flugsimulator ====
Ich gehe davon aus, dass du bereits einen Flugsimulator installiert hast. Folgende Simulatoren laufen mit der [[VATSIM]] spezifischen Software
(Squawkbox, FsInn, XSquawkbox) problemlos:

*Microsoft Flight Simulator 2004 ([[Squawkbox]], [[FsInn]])
*X-Plane 8.xx ([[XSquawkbox]])

==== Sonstige Software ====
Die meisten, am Markt erhältlichen Payware Flieger, haben sehr detailierte FMC's oder ähnliche Navigationseinrichtungen. Da
heutzutage auch in der Realität oft
ein FMC/FMS zum Einsatz kommt, wollen wir bei diesem Tutorial [[vasFMC]] als Referenz verwenden.
Mit diesem FMC kann fast jedes Freeware-Flugzeug verwendet werden.
Weiters ist es von Vorteil Tools wie [[VATSpy]] zu verwenden. Tools wie diese können dir
dabei helfen besetzte ATC Stationen zu finden und den Verkehr in deiner Umgebung im Auge zu behalten.

Beachte: Vor diesem Tutorial sollte die Dokumentation/Readme der jeweiligen Software studiert
werden und die Software danach konfiguriert werden.

=== Flugvorbereitung ===
Wie in der Realität, ist es auch bei [[VATSIM]] notwendig eine möglichst genaue Flugplanung durchzuführen, um auf gesicherten
Routen zum Zielflughafen zu kommen.

==== Flugplan ====
Beginnen wir mit dem VATSIM Flugplan. Dieser Flugplan hat im Wesentlichen zwei Aufgaben:
Zum einen dient er den Controllern im VATSIM Netzwerk dazu, deinen Abflug/Ankunfts - Flughafen, sowie Route und Callsign zu
zeigen. Er soll aber auch dazu verwendet werden, um anderen Piloten Einsicht in deine Absichten zu geben. Falls also gerade
kein Controller online ist, können Piloten in deiner Umgebung erkennen, ob sich eine gefährliche Annäherung zu dir entwickelt
oder nicht. 
Wir müssen nun also eine gültige Route und die passende Flughöhe dazu finden. Dazu besuchen wir die Seite
[http://vatroute.net/ http://vatroute.net]. Du siehst auf den ersten Blick, dass du lediglich zwei Felder ausfüllen musst: den Abflugs- und
den Ankunftsort. Geben wir also den ICAO Code [[LOWW]] für Wien als Abflugsort und [[LOWS]] für Salzburg als Ankunftsort
ein. Klicke nun auf '''Go!'''. Wir sehen nun unsere Route und links daneben den Bereich aus dem wir unsere Flughöhe wählen.
Achtung! Behalte diese Seite im Hintergrund in deinem Browser immer offen! Wir werden sie noch
des öfteren brauchen.

 
Jetzt werden wir den VATSIM Flugplan Schritt für Schritt ausfüllen. Besuche dazu die Seite von [http://vatsim.net VATSIM]. Unter
"Pilots Resources" findest du den Punkt "File Flightplan". Den Flugplan kann man auch im jeweiligen Pilotenclient
([[FSInn]], [[Squawkbox]], [[XSquawkbox]]) abgeben. Um aber ein einhetiliches Manual zu gewährleisten machen wir das direkt
über die [[VATSIM]] Seite (der aufgegebene Flugplan ist dann für 2 Stunden gültig).
Detailierte Informationen über den VATSIM Flugplan findest du auch
[http://usa-w.vatsim.net/prc/VPTPublic/122/122a/122a.htm hier]

===== Type =====
Hier geben wir an, ob wir den Flug nach Instrumentenflugregeln ([[IFR]]) oder Sichtflugregeln ([[VFR]]) durchführen wollen.
Wir wählen zunächst '''[[IFR]]'''. An anderer Stelle findest du einen VFR Beispielflug. Ausserdem wird dir dein Mentor sicher
gerne Fragen über [[IFR]] und [[VFR]] beantworten.

===== Callsign =====
Das Callsign ist jener Rufame eines Flugzeuges den der Controller auf seinem Radarschrim erblickt und über den er einen
Piloten auf der Funkfrequenz ruft. Wählen wir hier das Callsign '''AUA9834'''.
Meistens bestehen die Callsigns in der Realität aus dem Operator (AUA = Austrian) und der eigentlichen Flugnummer,
welche aus Buchstaben und Zahlen bestehen kann. Nach welchen Regeln ein Callsign in der Realität aufgebaut wird, sei hier
nicht weiter erwähnt. Wie der genaue Funkrufname (z.B.: DLH = Lufthansa) eines Callsigns lautet siehst du auch
[http://www.airlinecodes.co.uk/airlcodesearch.asp hier]. Du kannst auch gerne jedes andere Callsign verwenden, welches so
real wie möglich ist.

Achtung: Im VATSIM Netzwerk wird es gerne gesehen, wenn möglichst reale Callsigns verwendet
werden. Also das ICAO Callsign "AUA" und nicht z.B. das IATA Zeichen "OS" (welches auf
Flugtickets oder Passagierinformationen zu finden ist) für Austrian Airlines.

===== Aircraft Type =====
Wähle hier deinen Flugzeugtyp aus. Welche Bezeichnung eingefügt werden muss kannst du
[http://www.icao.int/anb/ais/8643/index.cfm hier] oder [http://usa-w.vatsim.net/prc/VPTPublic/pdfs/ac.pdf hier]
in Erfahrung bringen.
Welches Special Equipment du angeben musst kannst du
[http://usa-w.vatsim.net/prc/VPTPublic/122/122a/122a.htm hier] einsehen.
Generell (vor allem bei moderneren Flugzeugen) kannst du in diesem Feld folgendes eintragen: '''T/"aircraft type"/W'''.

===== True Airspeed =====
Hier gibst du an wie schnell du auf Reiseflughöhe sein wirst. Mit Flugzeugen wie der Boeing 737 oder einem Airbus wirst du
zwischen 420 und 470 Knoten schnell sein. Falls du den genauen Wert deines Flugzeuges kennt kannst du ihn hier eintragen,
falls nicht wählen wir den Wert 450 Knoten. Ein genauer Wert ist nicht notwendig, der Wert sollte aber plausibel sein.

===== Departure Point =====
Für unseren Beispielflug wählen wir Wien als Abflugort. Der ICAO Code für Wien lautet [[LOWW]]. Welche Stadt bzw. welcher
Flughafen welchen ICAO Code hat, siehst du [http://www.airlinecodes.co.uk/aptcodesearch.asp hier].

===== Departure Time =====
Gib hier deine geplante Abflugzeit an. Format: HHMM

===== Cruising Altidude =====

[[Category:Dokumentation]]

Example Flight

2008-07-05T17:18:49Z

Michael Rohrwasser: /* Sonstige Software */

== Beispielflug für neue Piloten ==

=== Einleitung ===
Dieser Flug, den wir Schritt für Schritt gemeinsam durchgehen wollen, soll dir einen ersten Auszug aus der Faszination der virtuellen Fliegerei
im [[VATSIM]] Netzwerk geben. Wenn du dich an diesem Tutorial orientierst kann eigentlich nichts schief gehen. Es wäre sehr
empfehlenswert dir einen
Termin mit deinem Mentor zu vereinbaren, damit ihr dieses Tutorial gemeinsam durcharbeiten könnt (z.B. über [[TeamSpeak]],
[[Skype]], etc.). Falls du
der Meinung bist, dass du das auch alleine packst können wir jetzt beginnen. Dein erster Flug wird von Wien nach Salzburg
führen.

=== Benötigte Software ===
Bevor es an die eigentliche Flugvorbereitung geht, sollten wir besprechen welche Software du verwendest bzw. welche Programme du benötigst.
==== Flugsimulator ====
Ich gehe davon aus, dass du bereits einen Flugsimulator installiert hast. Folgende Simulatoren laufen mit der [[VATSIM]] spezifischen Software
(Squawkbox, FsInn, XSquawkbox) problemlos:

*Microsoft Flight Simulator 2004 ([[Squawkbox]], [[FsInn]])
*X-Plane 8.xx ([[XSquawkbox]])

==== Sonstige Software ====
Die meisten, am Markt erhältlichen Payware Flieger, haben sehr detailierte FMC's oder ähnliche Navigationseinrichtungen. Da
heutzutage auch in der Realität oft
ein FMC/FMS zum Einsatz kommt, wollen wir bei diesem Tutorial [[vasFMC]] als Referenz verwenden.
Mit diesem FMC kann fast jedes Freeware-Flugzeug verwendet werden.
Weiters ist es von Vorteil Tools wie [[VATSpy]] zu verwenden. Tools wie diese können dir
dabei helfen besetzte ATC Stationen zu finden und den Verkehr in deiner Umgebung im Auge zu behalten.

Beachte: Vor diesem Tutorial sollte die Dokumentation/Readme der jeweiligen Software studiert
werden und die Software danach konfiguriert werden.

=== Flugvorbereitung ===
Wie in der Realität, ist es auch bei [[VATSIM]] notwendig eine möglichst genaue Flugplanung durchzuführen, um auf gesicherten
Routen zum Zielflughafen zu kommen.

==== Flugplan ====
Beginnen wir mit dem VATSIM Flugplan. Dieser Flugplan hat im Wesentlichen zwei Aufgaben:
Zum einen dient er den Controllern im VATSIM Netzwerk dazu, deinen Abflug/Ankunfts - Flughafen, sowie Route und Callsign zu
zeigen. Er soll aber auch dazu verwendet werden, um anderen Piloten Einsicht in deine Absichten zu geben. Falls also gerade
kein Controller online ist, können Piloten in deiner Umgebung erkennen, ob sich eine gefährliche Annäherung zu dir entwickelt
oder nicht. 
Wir müssen nun also eine gültige Route und die passende Flughöhe dazu finden. Dazu besuchen wir die Seite
[http://vatroute.net/ http://vatroute.net]. Du siehst auf den ersten Blick, dass du lediglich zwei Felder ausfüllen musst: den Abflugs- und
den Ankunftsort. Geben wir also den ICAO Code [[LOWW]] für Wien als Abflugsort und [[LOWS]] für Salzburg als Ankunftsort
ein. Klicke nun auf '''Go!'''. Wir sehen nun unsere Route und links daneben den Bereich aus dem wir unsere Flughöhe wählen.
Achtung! Behalte diese Seite im Hintergrund in deinem Browser immer offen! Wir werden sie noch des öfteren brauchen.

 
Jetzt werden wir den VATSIM Flugplan Schritt für Schritt ausfüllen. Besuche dazu die Seite von [http://vatsim.net VATSIM]. Unter
"Pilots Resources" findest du den Punkt "File Flightplan". Den Flugplan kann man auch im jeweiligen Pilotenclient
([[FSInn]], [[Squawkbox]], [[XSquawkbox]]) abgeben. Um aber ein einhetiliches Manual zu gewährleisten machen wir das direkt
über die [[VATSIM]] Seite (der aufgegebene Flugplan ist dann für 2 Stunden gültig).
Detailierte Informationen über den VATSIM Flugplan findest du auch
[http://usa-w.vatsim.net/prc/VPTPublic/122/122a/122a.htm hier]

===== Type =====
Hier geben wir an, ob wir den Flug nach Instrumentenflugregeln ([[IFR]]) oder Sichtflugregeln ([[VFR]]) durchführen wollen.
Wir wählen zunächst '''[[IFR]]'''. An anderer Stelle findest du einen VFR Beispielflug. Ausserdem wird dir dein Mentor sicher
gerne Fragen über [[IFR]] und [[VFR]] beantworten.

===== Callsign =====
Das Callsign ist jener Rufame eines Flugzeuges den der Controller auf seinem Radarschrim erblickt und über den er einen
Piloten auf der Funkfrequenz ruft. Wählen wir hier das Callsign '''AUA9834'''.
Meistens bestehen die Callsigns in der Realität aus dem Operator (AUA = Austrian) und der eigentlichen Flugnummer,
welche aus Buchstaben und Zahlen bestehen kann. Nach welchen Regeln ein Callsign in der Realität aufgebaut wird, sei hier
nicht weiter erwähnt. Wie der genaue Funkrufname (z.B.: DLH = Lufthansa) eines Callsigns lautet siehst du auch
[http://www.airlinecodes.co.uk/airlcodesearch.asp hier]. Du kannst auch gerne jedes andere Callsign verwenden, welches so
real wie möglich ist.

Achtung: Im VATSIM Netzwerk wird es gerne gesehen, wenn möglichst reale Callsigns verwendet werden. Also das ICAO
Callsign "AUA" und nicht z.B. das IATA Zeichen "OS" (welches auf Flugtickets oder Passagierinformationen zu
finden ist) für Austrian Airlines.

===== Aircraft Type =====
Wähle hier deinen Flugzeugtyp aus. Welche Bezeichnung eingefügt werden muss kannst du
[http://www.icao.int/anb/ais/8643/index.cfm hier] oder [http://usa-w.vatsim.net/prc/VPTPublic/pdfs/ac.pdf hier]
in Erfahrung bringen.
Welches Special Equipment du angeben musst kannst du
[http://usa-w.vatsim.net/prc/VPTPublic/122/122a/122a.htm hier] einsehen.
Generell (vor allem bei moderneren Flugzeugen) kannst du in diesem Feld folgendes eintragen: '''T/"aircraft type"/W'''.

===== True Airspeed =====
Hier gibst du an wie schnell du auf Reiseflughöhe sein wirst. Mit Flugzeugen wie der Boeing 737 oder einem Airbus wirst du
zwischen 420 und 470 Knoten schnell sein. Falls du den genauen Wert deines Flugzeuges kennt kannst du ihn hier eintragen,
falls nicht wählen wir den Wert 450 Knoten. Ein genauer Wert ist nicht notwendig, der Wert sollte aber plausibel sein.

===== Departure Point =====
Für unseren Beispielflug wählen wir Wien als Abflugort. Der ICAO Code für Wien lautet [[LOWW]]. Welche Stadt bzw. welcher
Flughafen welchen ICAO Code hat, siehst du [http://www.airlinecodes.co.uk/aptcodesearch.asp hier].

===== Departure Time =====
Gib hier deine geplante Abflugzeit an. Format: HHMM

===== Cruising Altidude =====

[[Category:Dokumentation]]

Study Guide:Airport Details

2008-07-05T17:16:04Z

Michael Rohrwasser: /* ATC Stationen in Salzburg */

== LOWW (Wien Schwechat) ==
=== Pisten ===
* '''11/29:''' Beton, 3500x45 Meter, ILS
* '''16/34:''' Beton, 3600x45 Meter, ILS
===Taxi Instructions===
The easiest way giving taxi instructions to aircraft is to: 
Taxi outgoing aircraft on taxiway MIKE (former OSCAR) ASAP.
Taxi incoming aircraft on taxiway LIMA (former INDIA) ASAP.
In this way, collision of aircraft should be avoided. Incoming aircraft on runway 16/34 vacating via B3 to B10 should use taxiway DELTA and LIMA (former INDIA). 
In case of a landing on runway 29 no aircraft is allowed to be in the extended runway centreline of runway 29 while landing aircraft is passing above. In this case aircraft should hold at ROMEO, FOXTROTT, SIERRA and GOLF and wait until the incoming aircraft touched down. 
You can also advise aircraft to follow behind another aircraft or give way to other taxiing aircraft. 
Austrian 125, follow Airbus 320 to holding-point runway 29
Austrian 125, give way to taxiing Airbus 320 passing from left to right
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible. 
Austrian 125, contact Tower on 119.40
'''Intersection take-off''' 
Intersection takeoffs can be granted by GND in coordination with TWR and in accordance or on pilot’s request. 

=== Visual Approches ===
Approaches using "Own Separation". Visual Approaches will be issued whenever the traffic situation permits. Due to several noise sensitive areas in the vicinity of Vienna Airport, LOWW_APP has to impose certain restrictions on visual approaches:
* NO visual or short approaches will be issued in the right-hand circuit for runway 16 and in the left-hand circuit for runway 11 (City of Vienna).
* Aircraft instructed to "maintain own separation" during final approach are expected to maintain a safe and efficient separation (normally less than 2,5 NM) to the preceding landing aircraft.
=== Possible Runway Configurations ===
The runway utilization concept for LOWW is based on the fact that the airport layout with it's crossing runways normally does '''not allow simultaneous approaches''' to both runways. So, whenever possible, runways 11/29 and 16/34 will be used independently to allow departures on one runway (normally 16 or 29) while using the other runway for landing aircraft. 
'''Possible runway configurations are:''' 
* ARR RWY 11 / DEP RWY 16 >>> SE winds, if no simultaneous approach possible
* ARR RWY 34 / DEP RWY 29 >>> calm/NW winds
* ARR RWY 16 / DEP RWY 29 >>> calm/SW winds
* ARR RWY 11/16sim. / DEP RWY 16 >>> calm/SE winds, simultaneous approach possible
Simultaneous approaches to runways 11 and 16 are conducted only at tower's discretion during certain weather conditions (visual reduction of separation). Aircrews are advised to show landing lights as soon as possible. 
In case of technical uncertainties during final approach - that might be possible lead to a missed approach - aircrews are asked to inform ATC immediately. 

===VFR Traffic===
VFR traffic can enter/leave the control zone (CTR) via sector SIERRA (to the south), sector ECHO (to the east) and along the Danube river on the route Klosterneuburg – Freudenau. Maximum altitude in these sectors is 1500ft or according to the VFR charts published online at www.vacc-sag.org. 

== LOWL (Blue Danube Airport) ==
=== Pisten ===
* '''09/27:''' Beton mit 3 Kilometer Länge und 60 Meter Breite
* '''09/27 (Gras):''' Graspiste mit 660 Meter Länge und 45 Meter Breite.

=== Anflugverfahren ===
Folgende Anflugverfahren beziehen sich nur auf die Piste 09/27. Die parallele Graspiste ist nur per Sicht anzufliegen.
*'''ILS:'''
** Richtung 27 bis CAT IIIb (109.30, Finalapproachtrack: 266°)
** Richtung 09 nur CAT I (110.55, Finalapproachtrack: 086°)
* '''VOR''' (LNZ, 116.600):
** Primär Richtung 09 (Radial 086)
** Mit Platzrundenanflug Richtung 27 (Radial 086, Wegbrechen nach Süden)
* '''NDB''' (LNZ 327):
** Primär Richtung 27 (Radial 266)
** Mit Platzrundenanflug Richtung 09 (Radial 266, Wegbrechen nach Süden)

=== ATC-Stationen in Linz ===
In Linz gibt es folgende zwei Stationen: 
* LOWL_TWR (Linz Turm) auf 118.800
* LOWL_APP (Linz Radar) auf 129.620

=== Besonderheiten in Linz ===
* In Linz dürfen Platzrundenanflüge (Visualcirclings) nur in südliche Richtung gemacht werden!
* Der Bereich südlich der Piste 27-09 ist militärisches Gelände!
* Für größere Flugzeugtypen stehen in Linz folgende Parkpositionen zur Verfügung:
** Position 13 bis zur Boeing 747-400
** Position 11 auch bis Boeing 747-400 (Wenn auf 11 und 13 B744 sind, kein Platz auf 12)

==LOWS (Salzburg Maxglan) ==
===Pisten===
* '''16/34:''' Beton mit 2.75 Kilometer Länge und 45 Meter Breite

=== Anflugverfahren ===
* '''ILS:''' Richtung 16 bis Special CATIII (109.90 OES, Finalapproachtrack: 156°)
* '''NDB:''' (SBG 382.0), primär Richtung 16 (Radial 156)
* '''Visual Circling:''', Richtung 16 bis SI 410.0 (Radial 336, wegbrechen nach links)

=== ATC Stationen in Salzburg ===
In Salzburg gibt es folgende Stationen:
*LOWS_DEL (Salzburg Delivery) auf Freq. 121.750 (an stark frequentierten Samstagen, sonst nur TWR) 
*LOWS_TWR (Salzburg Tower) auf Freq. 118.100
*LOWS_APP (Salzburg Radar) auf Freq. 123.720
*LOWS_F_APP (Salzburg Director) auf Freq. 134.97 (bei starker Verkehrsfrequenz)

==LOWI (Innsbruck Kranebitten)==
===Pisten===
* '''08/26:''' Betonpiste mit 2000 (6562´) Meter Länge und 45 Meter (148´) Breite

=== Anflugverfahren ===

* '''LOC/DME EAST''' (111.10 OEV)
* '''LOC/DME WEST''' (109.70 OEJ)

=== ATC Stationen in Innsbruck ===
*LOWI TWR (Innsbruck Tower) 120.100
*LOWI_APP (Innsbruck Radar) auf 119.275

==LOWK (Klagenfurt Alpe Adria Airport)==
=== Pisten ===
* '''10/28:''' Beton mit 2720 Meter (8294') Länge und 45 Meter Breite
* '''10R/28L''' Graspiste mit 710 Meter (2329') Länge

Folgende Anflugverfahren stehen für Klsgenfurt zur Verfügung für die Piste 10/28:
* '''ILS'''
**28: 110.10 (OEK) 285°

* '''NDB'''
**10: 405 (KW) 105°
**28: 374 (KFT) 273°

=== ATC-Stationen in Klagenfurt ===
* LOWK_TWR (Klagenfurt Tower) auf 118.100
* LOWK_APP (Klagenfurt Radar) auf 126.820
* LOWK_ATIS: 126.320

==LOWG (Graz Thalerhof)==
=== Pisten ===
* '''17L/35L:''' Grasspiste mit 760 (2493´) Meter Länge und 30 Meter (98´) Breite
* '''17C/35C:''' Betonpiste mit 3000 (9843´) Meter Länge und 45 Meter (148´) Breite
* '''17R/35R:''' Grasspiste mit 640 (2100´) Meter Länge und 25 Meter (82´) Breite

=== Anflugverfahren ===

Folgende Anflugverfahren stehen für Graz zur Verfügung für die Piste 17C/35C:

* '''ILS'''
**35C: 110.90 / 348°
**CAT II / III: 110.90 / 348°

* '''VOR/DME'''
**17C: 116.20 (GRZ VOR) / 168°
**35C: 116.20 (GRZ VOR) / 348°

* '''NDB'''
**35C: 290 (GRZ NDB) / 348°

* '''GPS'''
**35C: OWG01 / 348°

=== ATC-Stationen in Graz ===

* LOWG_TWR: 118.200
* LOWG_APP: 119.300
* LOWG_ATIS: 126.120

[[Category:Dokumentation]]

METAR

2008-07-05T17:01:37Z

Michael Rohrwasser: /* METAR */

== METAR ==
The word '''METAR''' comes from the French phrase "message d’observation météorologique régulière pour l’aviation". It is thought to be a contraction of the French words '''MÉT'''éorologique ("Weather") '''A'''viation '''R'''égulière ("Routine"). A METAR is a codified observation message indicating airfield weather conditions observed at a given time. Such a message is established every hour, even sometimes every 30 minutes or shorter due to fast and heavy weather changes which affects the traffic flow. 
Sample: 
LOWW 011220Z 33007KT 280V020 3000 R34/1500 +RASH FEW040 BKN058TCU 16/07 Q1014 RETS WS RWY34
34231091 BECMG -SHRA SCT030CB
 
=== Detailed explanation ===
1.) Location Identifier: '''LOWW''' 
The four-letter ICAO code of the observing location. 
 
2.) Day of Month/Zulu Time: '''011220Z''' 
 
3.) Wind: '''33007KT''' 
Wind direction (true heading), rounded to the nearest ten degrees and always expressed as three digits. Direction can be given as VRB if wind direction is variable and wind speed is at most 3 knots. 
plus 
average wind speed of last 10 minutes in knots. 
or 
maximum gust wind speed in knots. 
If it is calm, the wind is given as 00000KT. 
 
4.) Variable Wind Direction: '''280V020''' 
This field is used if the total variation of wind direction during the last 10 minutes is 60 degrees or more and wind speed is more than 3 knots. The direction extrema are given in clockwise order 
 
5.) Horizontal Visibility: '''3000''' 
Usually, only the minimum visibility is reported. If the minimum is less than 1500m and the maximum is over 5000m, the maximum visibility and its direction are indicated by a second visibility group following the minimum visibility. 
 
6.) RVR Runway Visual Range: '''R34/1500''' 
Runway designator and runway visibility in meters. 
 
7.) Significant Weather: '''+RASH''' 
Intensity is expressed by: + = heavy, - = light, ''nothing'' = moderate 
Proximity is described by: VC = ViCinity (within 8km) 
BC = Banc - fog bench
BL = Blowing
DR = Drifting
FZ = Freezing
MI = Mince - thin fog layer
SH = Shower
TS = Thunderstorm
DZ = Drizzle
GR = Grêle - hail (diameter > 5mm)
GS = Grêsil - hail (diameter < 5mm)
IC = Ice Crystal
PE = Ice Pellets
RA = Rain
SG = Snow Grains
SN = Snow
BR = Brume - mist (vis 1000 to 3000m)
DU = Dust
FG = Fog (vis < 1000m)
FU = Fumée - smoke (vis < 3000m)
HZ = Haze
SA = Sand
VA = Vulcanic Ashes
DS = Dust Storm
FC = Funnel Clouds
PO = Dust Spins
SQ = Squall
SS = Sand Storm
 
8.) Clouds and Ceiling: '''FEW040 BKN058TCU''' 
 
Cloud coverage: 
FEW = few - 1 to 2 octas
SCT = scattered - 3 to 4 octas
BKN = broken - 5 to 7 octas
OVC = overcast - 8 octas
Cloud types: 
CB = cumulunimbus
TCU = towering cumuli or cumulus congestus
Also common: 
SKC = Sky Clear (no clouds)
OVC/// = clouds covering the sky and which base is below aerodrome level
VV/// = sky not visible
VV002 = vertical visibility is 200ft
CAVOK = ceiling and visibility is OK (vis > 10km and SKC)
9.) Temperature and Dew Point: '''16/07''' 
The difference between temperature and dew pont is called "spread", the smaller the spread the higher the risk of precipitation. 
 
10.) Pressure, QNH (altimeter setting): '''Q1014''' 
QNH = 1014 hPa (hectopascals - 1hPa = 1mb - millibar) 
 
11.) Recent Weather: '''RETS''' 
Recent Thunderstorm 
Also: 
RERA = recent rain
RESN = recent snow
NOSIG = no significant change
12.) Wind Shear: '''WS RWY34''' 
Also: 
WS TKOF RWY 16 = windshear when taking of runway 16
WS LDG RWY 34 = windshear when landing at runway 34
WS ALL RWYS = windshear all runways
13.) Runway Status: '''34231091''' 
'''34''' = runway 34 
'''2''' = wet 
'''3''' = covering 26 to 50% of runway surface 
'''10''' = 10mm thick 
'''91''' = braking action poor 
Explaination: 
1st and 2nd figure = runway designator 
3rd figure = type of deposit on the runway 
0 = runway clean and dry
1 = damp
2 = wet
3 = frost
4 = snow
5 = wet snow
6 = slush
7 = ice
8 = compacted snow
9 = snow drift
/ = unknown, removal in progress
4th figure = percentage of runway contamination 
1 = less than 10%
2 = 11 to 25%
3 = 26 to 50%
4 = 51 to 100%
/ = unknown, removal in progress
5th and 6th figure = deposit thickness 
01 to 90 = millimeters
92 = 10cm
93 = 15cm
94 = 20cm
95 = 25cm
96 = 30cm
97 = 35cm
98 = 40cm
99 = unknown
// = unable to measure
7th and 8th figure = braking action 
01 to 90 = coefficient 0.01 to 0.90
or
91 = poor
92 = medium to poor
93 = medium
94 = medium to good
95 = good
99 = uncertain
// = unknown
14.) Trend: '''BECMG -SHRA SCT030CB''' 
Consists of following keywords and other METAR components: 
BECMG: becoming
TEMPO: temporarily
NOSIG: no significant change expected within 2 hours
AT: at
FM: from
TL: until
15.) Remarks: 
RMK followed by METAR components and miscellaneous abbreviations. 

== Links ==
*[[TAF]]

Study Guide:Tower

2008-07-05T15:32:07Z

Michael Rohrwasser: /* Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because Communication is crucially important for Air Traffic Control a fixed format and syntax us used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn
as soon as practicable

===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-05T15:31:16Z

Michael Rohrwasser: /* VFR Traffic - Differences */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because Communication is crucially important for Air Traffic Control a fixed format and syntax us used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß
oder darunter, QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below,
QNH 1014, Squawk 4607, right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound
route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5
miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn as soon as practicable
===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-05T15:27:19Z

Michael Rohrwasser: /* Merging Departing and Arriving Traffic */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because Communication is crucially important for Air Traffic Control a fixed format and syntax us used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for
immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is
now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß oder darunter,
QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below, QNH 1014, Squawk 4607,
right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn as soon as practicable
===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-05T15:25:48Z

Michael Rohrwasser: /* Arriving Traffic */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because Communication is crucially important for Air Traffic Control a fixed format and syntax us used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach,
wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline,
presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß oder darunter,
QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below, QNH 1014, Squawk 4607,
right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn as soon as practicable
===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-05T15:24:19Z

Michael Rohrwasser: /* Arriving Traffic */

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because Communication is crucially important for Air Traffic Control a fixed format and syntax us used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you,
continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach, wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline, presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß oder darunter,
QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below, QNH 1014, Squawk 4607,
right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn as soon as practicable
===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]

Study Guide:Tower

2008-07-05T15:23:06Z

Michael Rohrwasser:

==Introduction==
This Study Guide has been designed to give you all the information needed to start controlling as a Tower controller on the VATSIM network.

==Radio Communication - Basics==
Because Communication is crucially important for Air Traffic Control a fixed format and syntax us used, in order to minimize the risk of misunderstandings and to keep messages short. Worldwide English is the primary language in use, however in most countries you are also allowed to use the local language. In Austria VFR flights can choose their language whereas IFR flights are mostly conducted in English. Link: [[Buchstabiertabelle]]
===Basic Rules===
In order to achieve the goals set above the following rules important:
#''Listen before you talk''
#: It's impossible for two radio stations to transmit on the same frequency at the same time. If this is done, the radio signal will be blocked and this will result in a nasty noise on the frequency. Therefore it's important that every station monitors the frequency for about 5 seconds before transmitting, to make sure there’s no ongoing radio traffic. If you hear an ongoing conversation, wait until the conversation is over before you begin to transmit. Don’t start your communication if there is a read-back expected on the last transmission even if there is a short pause.
#''Think before you talk''
#: The radio traffic flow should be as smooth as possible. To achieve this it's vital to "think first" before transmitting so that a clear, concise and uninterrupted message can be sent.
#''As far as possible use standard phraseology and syntax''
#: To prevent misunderstandings and to maintain the radio traffic as effective as possible, stick to standardized phraseology and skip slang and of course private messages.

===Callsigns and Initial Contact===
Every participant on the network has his own Callsign. Controller Positions are identified by their location and their Function (e.g. Wien Radar, Graz Tower), Aircraft either by their Registration (e.g. OE-ALB) or an Airline Callsign followed by a combination of numbers and letters (e.g. AUA25LM, SWR387).
To pronounce these letters and digits the ICAO-Alphabet is used.
''
To initiate the contact between two stations an initial call has to be made. This call has the following structure:''
'''Station 1:''' Station 2, Station 1, Message
'''Station 2:''' Station 1, Station 2, Message
''Example - Austrian 251 is calling Wien Tower:''
'''AUA251:''' Wien Tower, Austrian 251, established ILS 34
'''LOWW_TWR:''' Austrian 251, Wien Tower, continue approach
In Subsequent calls the calling station part can be ommited. 
When a controller (or aircraft) transmits a message to a station it is very important that the receiving station acknowledge the message and reads back any required parts.. If the receiving station does not acknowledge, the transmitted message is considered as a lost transmission and the sender should resend the message or check if the receiving station got the message.
Items that must always be read back in full are all clearances (including altitudes, heaings, speeds, radials etc), runway in use, altimeter setting (QNH or QFE) and transition level, and all frequencies. For a controller, this is extremely important to remember, since if a pilot's readback is incorrect, the controller has to ask for confirmation, i.e a new readback. There are also items that should not be read back to reduce unnesessary radio transmissions. In short, this includes everything not mentioned above, but a few examples are: wind, temperature and other weather information (except altimeter settings) and traffic information in detail.
When giving an instruction the Callsign is stated at the beginning, when reading back you usually add it at the end of your transmission (although you are allowed to do it at the beginning too). 
'''Examples:'''
'''LOWW_APP:''' AUA251, turn left heading 290, descend to Altitude 5000 feet, QNH 1019.
'''AUA251:''' Turn left heading 290, descending to altitude 5000 feet QNH 1019, AUA251
 
'''LOWW_GND:''' OE-DLT, taxi to Holding Point Runway 29 via Exit 12, M and A1, give way
to Speedbird Airbus A320 crossing you right to left on M.
'''OE-DLT:''' Taxiing to H/P Rwy 29 via Exit 12, M and A1, giving way to Speedbird
Airbus A320 on M, OE-DLT.
 
'''LOWW_TWR:''' NLY2678, wind 330 degrees at 6 knots, Rwy 29, cleared for takeoff.
'''NLY2678:''' Rwy 29, cleared for takeoff, NLY2678.

==Aircraft and basic Flying Principles==
==METAR and TAF==
References for detailed information: [[METAR]], [[TAF]]

==How is an Aerodrome Organized?==
Der '''TWR (Flugplatzkontrollstelle)''' ist zuständig für den : 
Flugplatzverkehr
Personen und Fahrzeugverkehr auf Manövrierflächen
Nachdem Follow-Me Fahrzeuge nicht mehr eingesetzt werden dürfen entfällt hier der zweite Punkt. 
Die Flugplatzkontrollstelle kann nun auch weiter untergliedert werden in die Positionen Delivery (DEL), Ground/Rollkontrolle (GND) sowie Tower/Turm (TWR). 
 
Die nächst höher gelegene "Instanz" ist die '''APP (Anflugkontrollstelle)''' 
Kontrollierte An- und Abflüge
 
Die Anflugkontrollstelle in Wien ist für An- und Abflüge zuständig und kann bei Bedarf sektorisiert werden. So kann man den LOWW_APP in jeweils einen Nord-Süd Sektor teilen, oder aber in einen Upper-Lower Sektor
aufteilen. Zu Spitzenzeiten werden die Sektoren nach beiden Verfahren geteilt, noch dazu wird eine Director-Position eingerichtet, die LFZ vom Lower Approach auf das ILS führen. 
 
Darüber befindet sich die '''ACC (CTR) Bezirkskontrollstelle''' 
Für alle übrigen kontrollierten Flüge
Bei VATSIM bearbeitet der LOVV_CTR das gesamte Bundesgebiet und übernimmt auch die Tätigkeit des TWR & APP auf allen österreichischen Flughäfen, sollten diese nicht online sein. Das Gebiet Tirol & Vorarlberg
über FL165 wird nicht von LOVV kontrolliert, sondern im Auftrag der ACG von der deutschen Flugsicherung mitbetreut (EDMM). 
>br>
Alle drei Kontrollstellen üben den Kontrolldienst gemäß §68 Abs.1 LVR aus und erfüllen folgende Aufgaben:
'''Sicherheit gewährleisten''' durch
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen
Vermeidung von Zusammenstößen zwischen Luftfahrzeugen und Hindernissen auf den Manövrierflächen
'''Wirtschaftlichkeit gewährleisten''' durch raschen, flüssigen und geordneten Ablauf des Verkehrs
Diese Aufgaben gelten auch für den Controller in VATSIM, wenn auch aus anderen Beweggründen. In dem Wunsch so nahe an die Realität wie möglich zu kommen, sind diese Leitfäden unerlässlich. 

==Working Delivery Positions==
Clearence Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them.
===Flightplan Structure===
'''Flight plans''' are documents filed by pilots with the local Civil Aviation Authority prior to departure. They generally include basic information such as departure and arrival points, estimated time en route, alternate airports in case of bad weather, type of flight (whether instrument flight rules or visual flight rules), pilot's name and number of people on board. 
For IFR flights, flight plans are used by air traffic control to initiate tracking and routing services. For VFR flights, their only purpose is to provide needed information should search and rescue operations be required.

Aircraft routing types used in flight planning are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.
*'''Airway:''' Airway routing occurs along pre-defined pathways called Airways. Mostly aircraft are required to fly airways between the departure and destination airports. The rules cover altitude, airspeed, and requirements for entering and leaving the airway (SIDs and STARs).
*'''Navaid:''' Navaid routing occurs between Navaids (short for Navigational Aids) which are not always connected by airways. Navaid routing is typically only allowed in the continental U.S. If a flight plan specifies Navaid routing between two Navaids which are connected via an airway, the rules for that particular airway must be followed as if the aircraft was flying Airway routing between those two Navaids. Allowable altitudes are covered in Flight Levels.
*'''Direct:''' Direct routing occurs when one or both of the route segment endpoints are at a latitude/longitude which is not located at a Navaid. This is a routing from Vienna

===Issuing IFR Routing Clearances===
DEL gives routing clearances to all departing aircraft with the following information: 
'''Destination of aircraft'''
'''SID''' (= Standard instrument departure) Normally the filed SID is given
Initial climb altitude after departure (5000ft)
'''Squawk''' (Squawk assignments for LOWW are 4600 to 4620)
'''QNH''' (Local QNH of airport according to latest METAR)
CTOT (= Calculated take-off time) Slot time (Normally not used on the VATSIM network)

The '''bold''' marked points are mandatory, all other points are optional. 
 
Normal construction of a routing clearence:
Callsign, cleared to XXXX via XXXXX XX departure, (climb initially 5000ft), Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt via LUGIM 1C departure, climb initially 5000ft,
Squawk 4601, QNH 1020.
Some Aircraft are not able to follow SIDs for various reasons, most of the time due to missing equipment. In these cases you should issue a so called vectored departure. A vectored departure clearance includes the same components as a normal clearance but instead of the SID you issue instructions to be carried out after departure. In this case the initial climb altitude is mandatory.
Callsign,cleared to XXXX, after departure rwy XX, XXXXXXX, climb initially 5000ft,
Squawk 46XX, QNH XXXX
Example:
Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
expect vectors to LUGIM, initially climb to 5000 ft, Squawk 4601, QNH 1020.
You can find the instructions for each Airport within the [[Study Guide:Airport Details]]
If the pilot responds with a correct readback you should answer with the following phrase:
Callsign, readback correct.
Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures.

===Special Situations (High Traffic, Slots, ...)===
====Slots====
Um auch bei hohen Verkehrsaufkommen einen geordneten Verkehrsfluss zu gewährleisten und um Verspätungen in der Luft nach Möglichkeit gering zu halten, werden sogenannte Slots eingesetzt. Ein Slot ist der Zeitraum von fünf Minuten vor bis 10 Minuten nach der oben erwähnten CTOT. Innerhalb dieses Zeitfensters soll der Start des Flugzeugs von seinem Startflughafen erfolgen.
Im VATSIM Netzwerk wird dieses System nur in Ausnahmefällen, meistens bei Events eingesetzt.
==== Verhalten in Situationen mit erhöhtem Verkehrsaufkommen ====
Mitunter kommt es vor, dass eine der übergeordneten Positionen mit dem Verkehrsaufkommen nicht mehr zurecht kommt und keine neuen Flugzeuge mehr annehmen kann. In solchen Fällen sollte man den Start-Up der betroffenen Flugzeuge verzögern.

Piloten am Boden kann man mit Hinweisen auf die zu erwartende Verzögerung das Leben leichter machen:
Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.

== Working Ground Positions ==
Ground is responsible for all movements of aircraft on ground, except the movements on the runway.
Ground takes over responsibility for Delivery if he is not online. 
 
'''Start-up clearence''' 
Start-up clearence can be given if no other aircraft is taxiing behind the starting-up aircraft and if the take-off is expected in 20 minutes or less.
Austrian 125, start-up approved, (Temperature Minus 3)
'''Push-back clearence''' 
Push-back clearence can be given if no other aircraft is passing behind and the parking position requires push-back (i.e. position at the gate, … [refer to charts])
Austrian 125, push-back approved”
'''Combination of both phrases''' 
During low traffic you can use these two phrases together 
Austrian 125, start(-up) and push(-back) approved
===Taxi Instructions===
The pilot pushes back and starts the aircrafts engines. As soon as he is ready for taxi he will call you:
AUA125:AUA125, ready for taxi.
Depending on traffic you can give him the taxi instruction to his departure runway:
GND:AUA125, taxi to holding point Rwy 16 via taxiways Exit 4, L and F.
AUA125:Taxiing to holding point runway 29 via L and F, AUA125.
Sometimes it is necessary to hold an aircraft in front of another taxiway:
GND:AUA125, hold short of taxiway L.
AUA125:Holding short of L, AUA125.
When an aircraft is approaching its assigned holding-point (and clear of possible traffic-conflict) a hand-off to next higher position (i.e. TWR) shall be initiated as soon as possible.
GND:AUA125, contact now Salzburg Tower on frequency 118.10, bye bye!
AUA125:contacting Tower on frequency 118,10 bye!

===Ground Traffic Management===
To organise the traffic on ground different techniques are available, some of them relying on the pilots seeing each other. Generally you should avoid clearing two aircraft onto crossing pathways, unless you are sure they will never meet each other. To achieve this you should instruct aircraft to hold short of taxiways in the way stated above. Consider the following situation:
{|class="prettytable"
|-
|You are the Ground Controller at Vienna Airport. Runways active are 34 for landing and 29 for departure. DLH6KM has vacated rwy 34 and requests taxi to its parking position. LZB421 is ready for taxi at stand 7Q.
|}
GND:DLH6KM taxi to stand 40 via taxiways D and L.
DLH6KM:Taxiing to stand 40 via D and L, DLH6KM.
LZB421:Wien ground LZB421 stand 7Q, ready for taxi.
GND:LZB421, taxi taxiway W, hold short of taxiway L.
LZB421:taxiing via W holding short of L.
{|class="prettytable"
|-
|The aircraft are now both approaching the intersection L/W.
|}
GND:LZB421, give way to the DLH B737 crossing left to right on L, thereafter continue
taxi to holding point runway 29 via taxiways Exit 2, M and A1.
LZB421:Giving way to the 737 from left to right, then continuing taxi to holding point
runway 29 via Exit 2, M and A1.
Of course you have to make sure that this instruction is unambiguous, so there shouldn't be two DLH B737s in the area. Also in low visibility operations this procedure might not work very well, in this case you might have to give the aircraft the instruction to continue taxi when the other aircraft has passed.
In some cases it is also useful to let one aircraft follow the other:
GND:LZB421, follow the Austrian DASH 8 crossing you right to left on M to holding point runway 29.
LZB421:following the DASH 8 crossing us right to left on M to holding point runway 29.
===Intersection take-off===
Some flights do not need the whole length of their given departure runway so they might request takeoff from an intersection somewhere down the runway. This procedure is called a intersection takeoff. You should only grant this in coordination with Tower and if traffic situation permits.
Also at some airports intersections are used to be more flexible in the departure sequence (see section [[Study Guide:Tower#Departure_Seperation_-_Based_on_Type_of_Aircraft_and_departure_route|Departure Seperation]]).

===Special Situations (High Traffic, Slots, ...)===
====Slots====
In case the above mentioned slot regulations are in force ground has the responsibility to set up a departure sequence in a way that the aircraft do not miss their slot.
====Opposite runway operations====
At some austrian airports it is very common to use opposite runway configurations (departure and arrival runway are ooposite to each other). In these situations it can happen very fast that you have two aircraft facing each other nose to nose. Special attention should be paid to avoid this situation.

==Working Tower Positions==
Tower is responsible for all movements on the runways as well as for all movements within the control zone (CTR), (10NM radius, GND to 2500ft MSL). Tower is also responsible for ground and delivery if they are not online. He also decides which runways are in use.
===ATIS===
Bei der [[ATIS]] (Automatic Terminal Information Service) handelt es sich um eine automatisch generierte Informationsdurchsage für den Flugverkehr an größeren Flughäfen. Sie wird auf einer eigenen Frequenz in einer Endlosschleife gesendet und soll die aktiven Funkstationen am Flughafen entlasten. Piloten, die unter IFR an- oder abfliegen, sind verpflichtet, vor dem Erstkontakt mit der zuständigen Flugverkehrskontrollstelle zunächst das [[ATIS]] abzuhören. Beim Erstkontakt nennt der Pilot den [[ATIS]]-Kennbuchbuchstaben, um dem Controller zu bestätigen, dass er die aktuelle Version abgehört hat.
 
'''Bestandteile einer [[ATIS]] Meldung:'''
* Name des Flughafens
* Laufender ATIS-Kennbuchstabe
* Zeit der Beobachtung des Flugplatzwetters
* Aktive Landebahn
* Übergangshöhe
* Windrichtung und -geschwindigkeit
* Flugsichten
* besondere Wetterlagen (z.B. Regen)
* Hauptwolkenuntergrenze
* Temperatur und Taupunkt
* QNH
* Änderungstrend
Die [[ATIS]] wird alle 30 Minuten oder bei signifikanten Wetteränderungen erneuert. 

===Determination of active Runways===
Pilots normally prefer to takeoff and land the aircraft with the nose into the wind because it shortens the Rwy length required to safely operate the aircraft. The wind direction given in the METAR is the direction the wind is coming from, so it is easy to compare this wind to your given runways. 
'''Example:'''
{| class="prettytable"
|-
|You are the Tower controller at Salzburg Airport. The only runway at Salzburg is runway 16-34 so you have two directions available (roughly 160° and 340°.) The wind is coming from 180° at 5 knots. So the usual Runway in use would be rwy 16 for takeoff and landing.''
|}
However, at most airports a preferred runway configuration is defined (Find them here: [[Study Guide:Airport Details]]) which should be used if traffic situation and weather permits. Aircraft have certain limitations they can operate in, so normally the tailwind component should not exceed 5-10 knots (again depending on airport). Also the allowed crosswind is limited (This depends very much on the aircraft). 
Be aware that it is the pilots responsibility to accept a certain wind component and that this decision is often based on performance issues, so one pilot might accept the next one refuses to take a certain runway.

So back to our example above:
{| class="prettytable"
|-
|At Salzburg, due to the terrain in the vicinity and city of Salzburg around the airport, runway 34 is preferred for departures and rwy 16 for landing. So the indicated configuration would be DEP 34, ARR 16.
|}

===Transition Altitude/Transition Level===
Die Transition Altitude (TA) beträgt in Wien immer 5000 ft.
Der Transition Level (TL) ergibt sich in Abhängigkeit zum aktuellen Luftdruck (QNH): 
QNH < 0977: TA + 3000 ft.
QNH 0978 - 1012: TA + 2000 ft.
QNH 1013 - 1050: TA + 1000 ft.
QNH 1051 > : TA = TL

Zwischen der TA und dem TL befindet sich der Transition Layer, der einen Sicherheitsabstand von mindestens 1000 ft. zwischen dem "unteren Bereich" (Airport Elevation bis A5000 ft.) und dem "oberen Bereich" (Standard Luftdruck 1013 hPa bis Untergrenze TL) gewährleistet. Dadurch werden gefährliche Überschneidungen zwischen dem an- und abfliegenden Verkehr vermieden. 

===Runway Separation===
The runways are one of the most dangerous spots on an airport because aircraft are travelling at high speed with little room to maneuver and most of the time no ability to stop at a reasonable distance. Because of this the general rule is that '''only one aircaft may be cleared to use a runway at the same time.''' What this means practically and exceptions from this rule are explained in the following chapters.

===Departing Traffic===
So now we are at the point where the pilot reaches the Holding Point of his departure runway and reports ready for departure. What are the things you should check before issuing the takeoff clearance?
*Have a look at the flightplan. Take note of the type of aircraft and the Departure Route.
*Check the traffic approaching the runway.
To give him the takeoff clearance the following phrase should be used:
e.g.: TWR: AUA2CM, wind 320 degerees at 7 knots, Runway 29, cleared for takeoff.
AUA2CM: Cleared for takeoff Runway 29, AUA2CM
The pilot lines up on the runway, advances the throttle and takes off. When he is well established in climb check he is squawking Mode C and the right Code. Afterwards he is handed off to the next Controller, in this case a radar position:
TWR: AUA2CM, contact Wien Radar on frequency 128.20, bye bye!
AUA2CM: Contacting Wien Radar on frequency 128.20, AUA2CM.
The next aircraft reports ready for departure. Again check the points above, but this time we cannot give the takeoff clearance straight away because the preceeding aircraft is still occupying the runway. Now you get to know the first exception to the Runway Seperation rule above. To speed things up you can instruct the next aircraft to line up behind the first one while this one is still in the takeoff roll occupying the runway:
TWR: AZA639, behind departing Austrian Airbus A319, line-up rwy 29 behind and wait.
AZA639: behind departing Airbus lining up runway 29 and waiting behind, AZA639.
''Note: The two times behind in this instruction is not a typing error but was implemented
to emphasize that part of the clearance.''
This type of clearance is called a conditional clearance. 
The earliest possible point where you can issue the next takeoff clearance is, when the preceeding aircraft has overflown the opposite runway end or has clearly turned onto either side of it. 
However in some cases this could be very close which leads us to the next chapter.

===Departure Seperation - Based on Type of Aircraft and departure route===
One of the main tasks of air traffic control is to keep aircraft at a safe distance to each other. So imagine the following situation:
{| class="prettytable"
|-
|
*Two aircraft are departing right after each other.
*The first aircraft is a relatively slow Cessna 208 (~around 70 knots in climb), the second one a fast Boeing 767 (140-180 knots on the initial climb).
*Both follow the same departure route.
|}
Obviously it would not take long until the B767 catches up with the Cessna, a potentially very dangerous situation! You can see, that it is very important to check the flightplan of the aircraft you are about to clear for takeoff. 
The minimum radar seperation in the area around an airport is 3 nm or 1000 feet. These are the limits radar stations have to obey. Tower Controllers should aim to achieve the following seperation for departing aircraft following departure routes which share a common part:
<div align="center">
{| class="prettytable"
|-
|Fast followed by slow||3 nm
|-
|Matching Types||5 nm
|-
|Slow followed by fast||10 nm
|}</div>
In extreme examples like the one above it is often more advisable to coordinate with APP to find another solution. Often this involves clearing the aircraft to a non standard altitude or departure route:
TWR: DLH2441, after departure maintain runway heading, climb initially to 3000 ft
DLH2441: After departure maintaining runway heading, climbing to 3000 ft, DLH2441
TWR: DLH2441, wind 320 degrees at 9 knots, runway 29, cleared for takeoff
DLH2441: Cleared for takeoff runway 29, DLH2441
The other main task of ATC is to expedite the flow of traffic. Situation:
{| class="prettytable"
|-
|
*You have numerous aircraft departing from the same runway, following different departure routes. Some of them involve immediate right turns other SIDs immediate left turns.
*There are two holdingpoints available.
|}
It would benificial to use the gaps that arise between the aircraft using similar Departure Routes, so in close coordination with ground you should try to distribute aircraft over the holding points in a way to be able to fill those gaps.

===Departure Seperation - Based on Wake Turbulence Category===
There are two ways aircraft influence the air around them when passing through it:
{| class="prettytable"
|-
|
*Jetwash produced by the engines
*Turbulence created at the wings and especially at the wingtips
|}
This turbulence can cause severe problems or even loss of control for following aircraft.
The wake turbulence categories are based on the Maximum Takeoff weight (MTOW) of the aircraft:
<div align="center">
{| class="prettytable"
|-
| Light Aircraft (L)||< 7 000 kg
|-
|Medium Aircraft (M)||7 000 – 136 000 kg
|-
|Heavy Aircraft (H)||>136 000 kg
|}</div>
For departing aircraft, 2 minutes separation (3 minutes if the succeeding aircraft departs from an intersection) is applied when an aircraft in wake turbulence category LIGHT or MEDIUM departs behind an aircraft in wake turbulence category HEAVY, or when a LIGHT category aircraft departs behind a MEDIUM category aircraft. 
You may issue a take-off clearance to an aircraft that has waived wake turbulence separation, except, if it's a light or medium aircraft departing as follows:
{| class="prettytable"
|-
|
*Behind a heavy a/c and takeoff is started from an interception or along the runway in the direction of take-off.
*Behind a heavy a/c that is taking off or making a low or missed approach in the opposite direction on the same runway.
*Behind a heavy a/c that is making a low or missed approach in the same direction of the runway.
|}
To point out this hazard to a pilot the following phrase should be used:
TWR:ESK32C, behind departing heavy B777 line up runway 16 behind and wait,
caution wake turbulence.
ESK32C: behind departing B777 lining up rwy 29 and waiting, ESK32C.

===Use of the word takeoff===
The word take-off shall only be used in combination with the take-off clearence (cleared for take-off). For other phrases use the word departure (ready for departure – NOT ready for take-off!).

===Arriving Traffic===
Arriving Aircraft call you when they are established on an approach to a runway. Most of the time this is an ILS Approach but also other kinds are possible.
MAH224:Linz Tower, MAH224 established ILS Approach rwy 27.
Again you are not allowed to clear more than one aircraft onto the same runway at the same time. 
{| class="prettytable"
|-
|In order to issue a landing clearance
#preceeding departing traffic must have overflown the opposite runway threshold or clearly turned onto either side of the runway.
#preceeding landing traffic must have left the runway safety strip with all parts.
#traffic crossing the runway must have left the runway safety strip with all parts.
|}
If these conditions are met use the following phrase to clear the aircraft:
TWR:MAH224, Linz Tower, wind 300 degerees at 16 knots, runway 27, cleared to land.
MAH224:cleared to land runway 27, MAH224.
During periods of high traffic it is likely that you have more than one aircraft approaching the same runway at the same time. Approach has to ensure the minimum radar seperation of 3 nm and additionally increased seperation due to wake turbulence.
AUA26T:Linz Tower, AUA26T established ILS 27.
TWR:AUA26T, Linz Tower, continue approach, wind 300 degrees at 16 knots.
AUA26T:continuing approach, AUA26T.
{| class="prettytable"
|-
|Meanwhile MAH224 has left the runway.
|}
TWR:AUA26T wind 310 degrees at 14 knots, runway 27 cleared to land.
AUA26T:Runway 27, cleared to land, MAH224.
Often it is useful to give pilots additional information, such as traffic information or wind:
{| class="prettytable"
|-
|CSA276 is following NLY7751 (A320):
|}
CSA276: Wien Tower, CSA276 established ILS 34.
TWR:CSA276, Wien Tower, preceeding traffic is a NLY Airbus A320 3,5 nm ahead of you, continue approach runway 34, wind 010 degrees at 4 knots.
CSA276:We have the airbus in sight continuing approach, CSA276.
{| class="prettytable"
|-
|AUA81 is approaching runway 16, OE-AGA is on left base runway 16 and there is a rescue helicopter operating in the area around Freudenau.
|}
AUA81:Wien Tower, AUA81 established ILS 16
TWR:AUA81, Wien Tower, VFR traffic is on left base rwy 16, continue approach, wind 140 degrees at 7 knots.
AUA81:continuing approach, AUA81.
TWR:AUA81, There is an helicopter operating west of the extended centerline, presently at your one o'clock position, 5 nm, 1400 ft.
AUA81: Thank you, looking out, AUA81.
AUA81: traffic in sight, AUA81.
To give you an idea how dense traffic can get in real life consider that during peak times and good weather the seperation is reduced to 2,5 nm. This equals to one landing every 75 seconds. However on VATSIM the minimum seperation is 3 nm which already requires good cooperation from all the pilots involved.

===Merging Departing and Arriving Traffic===
And now to the most fun part of being a Tower Controller. Sometimes you get into the situation that you use the same runway for departures and arrivals. Either your airport has only one runway or weather demand this configuration.

Still the above rule of only one aircraft at the same time applies, however we also use conditional clearances which look very similar to those above in the departing traffic section.
LOWW_TWR: AUA123, Traffic short final RWY 29, C750, report in sight
AUA123: Traffic in sight, AUA123
LOWW_TWR: AUA123, behind landing C750 line up RWY 29 behind and wait
AUA123: Behind landing C750 lining up RWY 29 behdind and waiting, AUA123
To avoid misunderstandings, this time we make sure that the Pilot has the the landing aircraft in sight.
You don't have to worry about wake turbulence seperation between landing and departing aircraft since they never cross through each others wake.

To depart an aircraft in front of an approaching aircraft at the time of the departure clearance given the arriving aircraft should not be closer than 4 nm to touchdown.
To squeeze a departing aircraft between two arrivals you normally need a minimum of 6 nm between them. It is important for you to check carefully if you have the necessary gap, so have a close look at the distance between the arrivals and their speed. If the second one comes in faster than normal consider this in your calculation. Also you should make sure, that the pilot will be ready for departure when you need him to depart. To check this use the following phrase:
Callsign, are you ready for immediate departure?
Again it is a good idea to give the pilot an idea of the traffic situation around him.

Example:
{| class="prettytable"
|-
|You are the Tower Controller at Vienna airport. Runway 29 is active for departures and arrivals. One aircraft is on a 5 nm final, one at 12 nm out. Additionally you have two departures waiting at the holding point of ruwnay 29.
|}
TWR:CAL275, are you ready for immediate departure?
CAL275:Affirmitive, ready for immediate departure, CAL275
TWR:Traffic is now at a 4 nm final, wind 300 degrees at 7 knots, runway 29 cleared for immediate takeoff.
CAL275:cleared for immediate takeoff runway 29, CAL275
{| class="prettytable"
|-
|After the CAL B747 has taken off.
|}
TWR:AUA289, wind 300 degrees at 7 knots, runway 29, cleared to land.
AUA289:Runway 29, cleared to land, AUA289.
TWR:AUA2LT, traffic is an AUA Airbus A320 on a 2 nm final rwy 29, do you have traffic in sight?
AUA2LT:Traffic in sight, AUA2LT.
TWR:AUA2LT, behind landing traffic line up runway 29 behind and wait.
AUA2LT:Behind the landing Airbus, lining up runway 29 behind and waiting, AUA2LT.
{| class="prettytable"
|-
|AUA289 has vacated the runway.
|}
TWR:AUA2LT, wind 300 degrees at 8 knots, runway 29 cleared for takeoff, landing traffic is now on a 3,5 nm final.
AUA2LT:cleread for takeoff runway 29, AUA2LT.

==VFR Traffic - Differences==
The essential collision safety principle guiding the VFR pilot is "see and avoid." Pilots flying under VFR assume responsibility for their separation from all other aircraft and are generally not assigned routes or altitudes by air traffic control. Governing agencies establish specific requirements for VFR flight, consisting of minimum visibility, distance from clouds, and altitude to ensure that aircraft operating under VFR can be seen from a far enough distance to ensure safety.

To guide VFR TRaffic through youzr airspace you make use of VFR Routes, Sectors and reporting Points.
'''Used phrases''':
TWR:OE-AGA, enter control zone via VFR route Klosterneuburg – Freudenau, 1500ft or below,
QNH 1020, Squawk 4604, report XXXX (i.e. Freudenau), expecrt runway 29.
TWR:OE-AGA hold (orbit) overhead XXXX (i.e. Freudenau) in XXXX (i.e. 2500ft)

VFR flights should be guided into downwind, base and final leg for landing. 
TWR:OE-AGA, enter downwind for runway 29, report on downwind
TWR:OE-AGA, enter base for runway 29, report on base

VFR Flights get their Clearance from Delivery . After startup, they will contact Tower for taxi. A possible VFR Clearance could be: 
TWR:OE-AGA, verlassen Sie die Kontrollzone über Sichtflugstrecke Klosterneuburg, 1500 Fuß oder darunter,
QNH 1014, Squawk 4607, Rechtskurve nach dem Abheben so bald als möglich.
TWR:OE-AGA, leave controlzone via VFR-route Klosterneuburg, 1500 feet or below, QNH 1014, Squawk 4607,
right turn after departure as soon as possible.

TWR:OE-AGA, steigen sie auf 3500 Fuß, melden Sie Donauturm.
TWR:OE-AGA, climb 3500 feet, report Donauturm.

In the air ATC provides traffic information.
TWR:OE-AGA, Traffic at your 12 o'clock position, 2100 feet, a PA28 on VFR inbound route Klosterneuburg-Freudenau.

When the aircraft leaves the controlzone.
TWR:OE-AGA, set Sqauwk 7000, leaving frequency is approved.

Wien Tower/Turm can also be contacted in German.

===Merging in VFR Traffic===
To manage VFR Traffic efficiently you have to use traffic information and visual seperation.
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
Because of other traffic it might be necessary for the aircraft to remain in the downwind leg until the traffic has passed:
TWR:OE-AGA, fly extended right downwind, standby for base.
OE-AGA: Extending right downwind, OE-AGA
To instruct the aircraft to continue it's approach use the following procedure:
TWR: OE-ANX, traffic at your 3 o´clock position, moving right to left, B767, distance 2.5 miles, report mentioned traffic in sight
OE-ANX: Traffic in sight, OE-ANX
TWR:OE-AGA, behind B767 traffic, enter final RWY 29, caution wake turbulence
OE-AGA: Behind B767, enter final RWY 29 behind, caution wake turbulence, OE-ANX
When using an extended downwind you should always consider that the aircrafts speed might be considerably lower than the speed of other aircrafts involved. So if an aircraft has to fly a long way out it might take some time for it to come all the way back, generating a big gap in the arrival sequence. Instead you should aim to keep the plane within the vicinity of the airfield:
TWR: OE-AGA, Make a right three-sixty.
OE-AGA: Making three-sixty to the right.
TWR: OE-AGA, Orbit left
OE-AGA: Orbiting left, OE-AGA
The second instructions means, that the pilot should make orbits until further advice.
===Information Positions===

==Special Situations (High Traffic, Slots, ...)==
===High traffic situations===
During high traffic situations communication with adjacent approach sectors is very important. Especially during single runway operations you might have to ask for increased inbound spacing to be able to fit in departing aircraft.
===Phrasenzusätze in Situationen mit erhöhtem Verkehrsaufkommen===
Um den Piloten eine Anweisung mit Nachdruck bekannt zu machen sollen folgende Phrasen angehängt werden. Dies ist vor allem bei der Runway Sseparation anzuwenden.
Austrian 125, wind is xxx/xx runway 29 cleared for takeoff, expedite
Für Traffic im Anflug, eine Möglichkeit die Runway schneller frei zu bekommen:
Austrian 125, wind is xxx/xx runway 34 cleared to land, vacate runway as soon as practicable
Um VFR Traffic rasch aus dem Abflugsektor zu bekommen gibt es folgende Möglichkeit:
OE-ABC, wind xxx/xx, runway 29 cleared for takeoff, after departure right turn as soon as practicable
===Opposite runway operations===
This is one of the more difficult situtions for a Tower controller. You have to consider the departure route of each aircraft to estimate the required spacing to arriving traffic. Again close coordination with approach is very important.

== Ressourcen ==
* [http://www.vateud-td.org/ VATEUD Training Department]
* [http://de.wikipedia.org/wiki/ICAO-Alphabet Wikipedia: Buchstabentafel]
 
[[Category:Dokumentation]]