Study Guide:Delivery

Introduction

This Study Guide has been designed to give you all the information needed to start controlling as a Clearance/Delivery controller on the VATSIM network. It assumes, that you have read and understood the Study Guide:OBS before.

How is an Aerodrome organized

As airports grew bigger over time also the workload for the Air Traffic Controller handling the traffic got bigger. Soon it was necessary to distribute this workload onto more than one controller in order to be able to cope with the traffic.

So the Tower Position got divided into thre basic types with different areas of responsibility.

1. Clearance delivery (DEL), responsible for checking flightplans and issuing IFR clearances to departing aircraft.
2. Ground (GND), responsible for all traffic on the apron and the taxiways.
3. Tower (TWR), responsible for movements on the runway and within its associated Control Zone.

Because Tower and Ground controllers rely very strongly on what they see out of their window, these are the positions which are situated within the airports control tower.

Apart from that there are the controllers who manage the traffic once it has left the control zone. They are again divided into:

1. APP Positions, managing the traffic within the airports vicinity (the so called TMA, Terminal Area). In Austria they are situated directly at the airports.
2. ACC (Area Control Center, on VATSIM the abbreviation CTR is used) positions, which are responsible for enroute traffic. They reside in Vienna.

If the air is too crowded, APP and CTR can be divided horizontally (lower and higher APP), vertically (north APP and south APP), or a director responsible for approach spacing - but we won't want to make it too complicated for now. Local procedures and agreements regulate it, how this is done.

• Since they all use their radar to control air traffic, they are also called Radar positions.

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Working Delivery Positions

Clearance Delivery is responsible for checking and correcting flightplans of departing aircraft and issue routing clearances to them. This task may sound boring, but is important for upstream controllers: Clearances take time (on the radio) and may block vital commands (like takeoff and landing clearances), and radar stations rely on the checked and cleared values (SIDs and clearance altitudes) for their controlling. If DEL makes mistakes, APP will notice.

There are 2 types of flight plans at VATSIM:

• IFR: Any pilot who flies IFR must file a flight plan. It contains the exact routing from departure to arrival, cruise altitude and some more information which controllers need for their job.

• VFR: VFR pilots can file flight plans, but they don't need to. They can simply ask for taxi clearance, take off and continue in uncontrolled airspace.

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.

Aircraft routing types used in IFR flight plans are: Airway, Navaid and Direct. A route may be composed of segments of different routing types.

1. 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).
2. 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.
3. 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.

For VFR flights, their only purpose is to provide needed information should search and rescue operations be required. At VATSIM, a VFR flight plan is handy for controllers, as it shows vital information with the airplane tag on the radar, like the destination.

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Workflow for DEL controllers

At VATSIM, he journey starts with an aircraft popping up at an airport. Initially, the tag (in Euroscope) will show "NOFP", meaning: No flight plan filed so far. Some time later, a destination and more will show up, and that means: The pilot has filed a flight plan. On this point, DEL controller work starts. At this point, Euroscope has done already some work for you. DEL's job is to check and complete it, and to give clearance to the pilot.

1. Setup

When you log in as DEL, you have to do two things (if waiting pilots jump on you, tell them to stand by until you have done it!):

1. Check with the upstream controller (TWR, APP, CTR) for active runways and set active airport and runways in your Euroscope "active runways" dialogue box.
2. Check with the upstream controller the active ATIS letter. Set your ATIS dialog box to your airport and the active letter, but don't connect (ATIS is TWR's job). Set this way, Euroscope will show the valid ATIS letter in your METAR list and you don't need to ask every few minutes. If there is no ATIS, then check active runway and wind, as you will need to tell this to pilots.

2. Check the flight Plan

Then you turn to the waiting pilots and work them down one by one. First, Check, if it is a VFR or IFR flight plan.

For IFR flight plans, ...

• Check, if "From"-Airport is correct and "To"-Airport makes sense. If not, then ask the pilot to refile the flight plan.
• Check, if departure runway corresponds to the active runway. If not, then check your runway settings in Euroscope.
• Check, if cruise altitude is correct: Cruise altitude is stated in flight levels (hundreds of feed): FL280 means 28000 feet (at QNH 1013, to be really correct). For flight levels below FL300, westbound flights have even flight levels, and eastbound flights have odd flight levels. If the cruise altitude, ask the pilot for the nearest correct altitudes 10 FL up or down.
• Check, if there is a valid SID from the active runway to the first waypoint in the flight plan. If not, then look for the cause. It could be an invalid flight plan (a flight plan must contain a waypoint which is the end of a SID - most SIDs have the waypoint in their names: SITNI5B is the SID leading from LOWW rwy 16 to SITNI). If the flight plan does not contain any valid waypoint, ask the pilot to refile a correct flight plan. If the flight plan is correct, then you might need to manually select the best SID.
• Euroscope has already selected the first matching SID in the alphabet. Check, if this SID is applicable to the aircraft and time (you might want to check with APP to clarify, which SIDs are correct), and select the best SID.

For VFR flight plans, the task is easier. usually, it contains the destination and a verbal description of the pilot's intention (could be "circuits" or "platzrunde", or "LOWL via Donau").

• Check, if this intention is possible and makes sense (you might check with TWR).

2. Set Squawk and initial clearance altitude

• Set a squawk now. The squawk number space is predefined for each airport and written in the sector file. For normal purposes, automatic squawk allocation in Euroscope works fine. In high traffic situations like Finally Austria, the squawk space runs out quickly, and Euroscope runs mad. The result is duplicate squawks. Technically, this is not a problem at VATSIM (as plane-data links are made by pilot ID, not by squawk code), but in reality this would be a nightmare. In this case, you have to set squawk codes by hand and start to fill other squawk number spaces, like 2500+. Don't attempt to set a squawk with a number higher than 7 - squawks are octets and don't have 8 and 9 (4707 is good, 4708 does not work).
• Set the initial climb altitude. This differs from airport to airport. LOWW has 5000ft for all SIDs ("A50" in the list), LOWI has FL160 for all SIDs, and Salzburg has different altitudes for different SIDs (look into the SID description).

3. Wait for initial contact

ATC is a service job - you wait for the pilot to come to you, as in real life you don't know if the pilot is on your frequency at all. At some point, the aircraft will call you, ideally with the first (long) phrase. When congested, the short form is used:

LHA123: Wien Delivery, servus. Laipzich Air 123, gate C31, Fokker 70, requesting clearance to München, Info B on board.
LHA456: Wien Delivery, Laipzich Air 456 ready for clearance.

4. Issue IFR Routing Clearances

First, clear everything which is wrong or unclear in the flight plan, like ...

DEL: Leipzig Air 123, servus. Cruise altitude must be odd, confirm flight level 310 or 290?
LHA123: Flight level 310, Leipzig Air 123.

Then, issue your clearance:

DEL gives routing clearances to all departing aircraft with the following information:

Destination of flight
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)
ATIS (which ATIS letter is current)
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, (initial climb 5000ft), Squawk 46XX

Example:

Austrian 125, cleared to Frankfurt via LUGIM 1C departure, initial climb 5000ft,
 Squawk 4601, info B is current.

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, initial climb 5000ft,
Squawk 46XX

Example:

Austrian 125, cleared to Frankfurt, after departure Runway 29, turn left heading 240
 expect vectors to LUGIM, initial climb 5000 ft, Squawk 4601.

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. Austrian 125, readback correct

5. Handover

Afterwards you either hand the pilot over to GND or wait for his startup request, depending on local procedures. You can do this joint with the readback answer, like:

Austrian 125, readback correct, call Ground at 121.60.

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Special Situations (High Traffic, Slots, ...)

Missing ATIS

• Maybe there is no upstream controller. Then you ask the pilot, which runway he wants to use. Then you can clear him.
• Maybe there is a technical problem and TWR cannot connect any ATIS. In this case, you have to check with TWR, which runway is in use, and get the METAR yourself from Euroscope. If the pilot does not find any ATIS, he/she should contact you with the following phrase. Anyway, you should answer him as follows, before any other clearance is given:

LHA123: Wien DEL, Leipzig Air 123, Position E42, requesting airport information.
DEL: Leipzig 123, Wien Delivery, servus. Active runway is 34, wind 320 at 10, QNH 1030.

VFR flight plans

... are easier to clear. After checking, you set a squawk. You read back the information of the flight plan and hand over to ground for taxi, like:

DEL: OE-DLT, cleared left hand traffic patterns runway 16, squawk 4621.
OE-DLT: cleared left hand traffic patterns, squawking 4621.
DEL: OE-DLT, readback correct, contact Ground  on 119.4, bye!

Slots

In order to guarantee a safe flow of traffic and to minimize delays in the air so called slots are being used. A slot is a timeframe of five minutes before to ten minutes after the CTOT mentioned before. The aircraft has to depart within this timeframe from its departure airport. On the VATSIM network this system is only used on special occasions.

Behavior in situations with increased traffic

Sometimes one of your neighboring sectors has to stop accepting traffic. In these cases you should delay an aircrafts start-up clearance.

If possible you should inform the pilot about the expected delay:

Austrian 125, readback correct, expect startup in 10 minutes.
Austrian 125, startup approved, expect departure in 10 minutes.