Difference between revisions of "Emergency procedures"

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=== Priority Landing  ===
=== Priority Landing  ===
This is an easy case: A fully functional and communicating aircraft has only one grievance: Get down as soon as possible. Most reasons are medical emergencies, live organs, low fuel (at too low fuel this is an emergency), or VIPs on board (feel free to send him into 2 hours holding and divert to GATB if it is Karl-Heinz Grasser).
Handling is easy: Issue instructions (vectors, descent, and on ground: a gate close to arrival) that best meet his/her request.
This is an easy case: A fully functional and communicating aircraft has only one grievance: Get down as soon as possible. Most reasons are medical issuse, live organs, low fuel (at too low fuel the pilot will report an emergency), or VIPs on board. Also government flights can request priority handling.<br>
Handling is easy: Issue instructions (vectors, descent, and on ground: a gate close to arrival) that best meet his/her request.  

Revision as of 22:19, 27 March 2012


Emergencies and abnormal procedures arise from two directions: from the pilots or the ATC- depending where actually they occur. If a pilot gets into trouble then he decleares an emergency. If for example the runway is blocked (damaged aircraft, animals etc.) then the ATC reports abnormal procedures to the surrounding stations.

It is quite common that the emergency call does not come right away. The crew might discover something (an indicator in the cockpit) and follows the letters: DODAR (Diagnose, Options available, Decide, Allocate task, Review). In this case, a short message to ATC is common, that something is wrong:

LHA123: Tower, Laipzich Air 123, we have a problem, standby.
TWR: LHA123, roger.

If you are controller and hear this, prepare yourself: Oversee the situation, you might wait with the next takeoff clearance, think of scenarios like: where could the aircraft turn back? Which diversion can it reach? The pilot will call you back in a few seconds with precise information.

Abnormal procedures


Pan-Pan is an urgency announcement of the crew, which is used if an aircraft or its occupence are endangered but not acute at risk (so no need for immediate action), and the crew calls for a preferential treatment. The crew can mostly continue flying under normal or restricted conditions and usually also land regularly.

SWR111:   Swissair one-eleven heavy is declaring pan-pan-pan. We have smoke in the cockpit. Request immediate return to a convenient place, I guess Boston.
CZQM_CTR: Swissair one-eleven heavy, pan-pan received, turn left direct Boston VOR, climb and maintain flight level 310.
  • Pan-pan is only a message that the crew has to fly under abnormal circumstances and eventually needs a higher priority as non-pan flights.

Radio communication Failure (RCF)

You notice RCF at the SQ 7600, which lights up the letters "RDOF" in the aircraft tag of Euroscope. But maybe it is you who discovers RCF first - crew might not know it yet. In this case, assume the aircraft continues as filed, and you have to clear the way.

  • First, determine what RDOF it is: does the pilot hear or is his aircraft completely deaf? For this purpose, you ask the following:
Controller: Leipzig 123, received radio communication failure. If you read, squawk Ident.

If an ident signal is received, then things are easier: The pilot can receive calls normally, but might need to land priority. If the pilot sends no ident signal, then you (and even more important: the pilot...) needs to know the RCF failure procedures. The airplane will follow this procedure and land. Controller's job is...

  • to get other pilots out of the way
  • to inform other ATC "upstream" about the situation
  • to monitor the aircraft: A RDF failure could turn into an emergency (you don't know, what's all wrong in the plane), and the pilot might not strictly follow the RDF procedure. Remember that the pilot needs the radio for local QNH, which might have changed since departure (local QNH at destination is part of the briefing).
  • to bear in mind that the runway config might have changed and the pilot still approaches the "old" config.

A RDF procedure typically follows the pattern:

  1. If the pilot has received the airport info (ATIS or other), then it will follow it (QNH, runway in use). Caution: The only way to determine this is if there has been contact, for example with APP, where the pilot has reported "ATIS on board".
  2. If the pilot has not received it, then it will follow standard runway configuration according to the charts.
  3. Typically, procedures include flying standard STAR and transition and flying the minimum altitudes described in the charts. Some airports include holdings for a predetermined time.

See the RCF procedures for [LOWW]. Hey guys, where are the RCF procedures for the other LOVV airports?

Go Around and missed approach

A Go-Around can be seen as abnormal procedure. Two different procedures can be followed:

  1. Missed Approach published in the Charts. APP should be informed about it (via teamspeak or PM).
  2. Individual handling like heading and altitude. This has to be coordinated with APP.

Remember: If necessary for safety, TWR can (and must) tell the aircraft virtually anything the aircraft is able to. If the reason for go-around is in the direction of the go-around procedure, then "proceed as published" does not really make sense. TWR might tell the aircraft to turn off left or right immediately.

Phraseology differs according who announces it:

  • If ATC issues go-around, then the phraseology expresses urgency. Listen to the readback - it is vital that the pilot received it. In this example, the go-around is individual:
TWR: Leipzig 123, go-around, say again go-around, turn left immediately direct SNU, climb 5000ft.
LHA123:LHA123 is going around, turning left SNU, climbing 5000ft.
  • If the pilot goes around, then he/she announces it. In this example, standard go-around pattern is used:
LHA123: Lepzig 123 goes around.
TWR: Roger, Leipzig 123, go around as published

As a courtesy, you could tell the pilot the go-around procedure anyway - many of them don't know it.

Rejected take-off

Rejected take-off procedures can quickly turn into a nasty situation, if ATC does not react immediately and correctly.

If the pilot rejects take-off

Then the approaching traffic should immediately receive go-around instructions and the APP should be informed about it. Do not expect the aircraft to leave the runway immediately - something serious might be wrong, so be prepared to change the runway (if you have, like in LOWW).

If TWR withdraws take-off clearance

The situation is even worse, as the aircraft might be rolling already and be beyond v1 where it can't stop (and you as TWR don't know the specific V1 speed). In this case, TWR has to do the following:

If the aircraft has commenced take-off:

"(Callsign) Stop immediately. I say again (Callsign) stop immediately - acknowledge".

If the aircraft has not commenced take-off:

"(Callsign) hold position. Cancel take-off - I say again, cancel take-off - acknowledge".
  • If you have arriving traffic you must assume go-around instructions until the runway is free for the next approaching aircraft.

Malfunctions of airport navigation equipment

Malfunctions of airport equipment (broken ILS, VOR or NDB) cannot be simulated at VATSIM (navaids are part of pilot software). If an aircraft has broken equipment, then this is actually a "pan-pan" case and should be treated as such.

It could happen that a pilot reports a malfunction (in case his software simulates such a failure - but this failure only affects him. And Still, you could simulate airport malfunctions for all pilots and see, what they will do. In this case, you should know the other approaches available, offer alternatives (and communicate them between TWR and APP). If weather permits, you can offer visual approaches.

Priority Landing

This is an easy case: A fully functional and communicating aircraft has only one grievance: Get down as soon as possible. Most reasons are medical issuse, live organs, low fuel (at too low fuel the pilot will report an emergency), or VIPs on board. Also government flights can request priority handling.

Handling is easy: Issue instructions (vectors, descent, and on ground: a gate close to arrival) that best meet his/her request.

Runway closure

This procedure is triggered by the TWR controller. There are two different cases:

  • Immediate closure: If the runway has to be closed immediately (broken down aircraft, debris, deer, ...), then the runway closure is imminent:
  1. approaching traffic receives go-around
  2. APP receives request, not to hand off any more aircraft
  3. GND receives information to halt taxi clearances to this runway
  4. New runway is opened, GND and APP informed (or airport closed)
  5. ATIS adapted.
  • Step-by-step closure: If the reason for closure can be forseen (wind changes slowly, noise abatement rules, then the runway closure is more orderly:
  1. APP receives request not to hand off any more aircraft and/or divert to new runway
  2. GND receives request not to issue taxi clearances tot his runway, and the new one
  3. Remaining aircraft receive landing clearance
  4. New runway will be opened
  5. ATIS adapted
  6. APP and GND are informed.

Emergencies - 4 phases

If a pilot discovers a condition of being threatened by serious and/or imminent danger and of requiring immediate assistance, then he/she will issue an emergency call.

A basic principle is important: The pilot is in command, ATC is here to assist. Don't tell the pilot how to fly the aircraft - it's not your job, and you are not there. The pilot says his intentions, and ATC reacts. This does not mean that you don't order the pilot to do things, but they should be according to his/her intentions, not yours.

Mayday procedure has the following phases:

1) Mayday call by the pilot:

LHA123: Mayday, mayday, mayday. Laipzich Air 123 engine failure. Descending below FL240, Request vectors to nearest suitable airfield.
LOWW_APP: Leipzig Air 123, mayday call received, engine failure. Squawk 7700. Next airfield is Vienna Airport, turn left 020°, 60 miles.

Pilot calls "mayday" three times, the nature of his/her emergency, what his/her intentions are and what he/she needs now. ATC reads back, tells him to set transponder to 7700 (then all ATC see his mayday call on the Euroscope screen: The tag turns red and is preceded with "EMG"). Then the aircraft gets the needed information.

2) standard response by ATC

The pilot has a few seconds to do (avigate, navigate), and ATC too: He/she needs to inform other pilots and fellow ATC stations.

LOWW_APP: All stations, all stations, emergency in progress. [no calls, no readbacks].

With this call pilots know: They should continue as told (their SID, transitions, STAR). They only call ATC, if safety is at stake. If they receive ATC orders, they don't read back - they just do it.

Then ATC informs other controllers via intercom, Text or teamspeak, and collects the necessary information.

LOWW_APP->LOWW_CTR: mayday LHA123, engine failure, no handoffs
LOWW_APP->LOWW_TWR: mayday LHA123 engine failure, request rwys available
LOWW_TWR->LOWW_APP: all rwys available, wind 320°6kt

Generally, the controller makes sure that he/she does not get any traffic any more: no takeoffs from below, no handoffs from above.

Beyond this point, there is no fixed phraseology. ATC speaks with pilots to make sure that he is served best. With the information gathered, ATC will turn back to the pilot and figure out next steps.

LOWW_APP: Mayday-Leipzig 123, Vienna reports all runways available, 52 miles to final, for runway 11 maintain present heading, wind 320°4kt. When able, report situation.
LHA123: Leipzig 123, left engine out, right engine 40%, descending 1800, 48 passengers and 5 crew on board, fuel for 1 hour.

ATC's information is important to pilots: Where can I land and how far it is? Pilots say, that accurate distance is vital, so use the distance tool on your scope.

The pilot's first information is important for controllers: What is wrong? That says a lot about the ability of the pilot to control the aircraft. The last info is important for real life: Emergency services on the ground need to prepare for rescue.

3) All following measures

There is no strict rules beyond the standard response. Pilot and ATC communicate the way that suits best their situation. The following guidelines are vital:

  • Pilot tells, ATC delivers. On the flight plan, you read "PIC - pilot in command" - let him stay in command, and let him decide, which command he wants you to take over.
  • Communication: least possible, as precise as possible. During an emergency, the cockpit is a beehouse. The more time pilots have for themselves, the better. If a pilot does not answer: stay calm - the pilot might follow the rule 1-avigate 2-navigate 3-communicate and might not have reached step 3. He/she may say "ATC standby" or just nothing. To quote a real-life example: [don't do this.]
  • Clear needed airspace: Noone needs to turn away, if he/she is not in the way. Some traffic might continue as normal. You might consider premature handoffs to other controllers or holdings. As a rule of thumb: don't produce more emergencies than you have already.
  • Pilot has the choice of frequency: An aircraft can stay on the frequency (eg. TWR) through all stages of his/her emergency or change, if he/she wishes. ATC will adjust. Assume that you have an engine failure at FL100 approaching LOWW. The pilot is on the APP frequency and does not want to change. Either APP coordinates with TWR landing clearance and issues it, or TWR enters the APP frequency and issues landing clearance him/herself.

4) End emergency procedure

At some stage, the emergency is over, and the aircraft is happily on the runway or unhappy in the wood. At this stage, all other pilots and ATC need to know that it is over:

LOWW_APP: All stations, emergency procedures terminated. All operations return to normal.

Then, cleanup starts: There might be a dozen aircraft in holdings to bring in, runways to clean and aircraft on ground to get out.

Emergencies - the cases

This list is open - be prepared to react to the unusual. If you discover an emergency which is not covered here, feel free to add it.

Loss of Cabin pressure

This could be a problem in high traffic situations. The pilot will immediately begin an "emergency descent" to FL100 or below (he won't wait for approval). As controller, you can expect that the pilot wants to land as soon as possible. Be prepared that the emergency situation escalates, as there is a reason for the loss of cabin pressure which could cause other systems to fail too.

Loss of Hydraulicpressure

This is a major problem, depending on the degree of failure: On large aircraft, all systems for manoever depend on hydraulic pressure. First thing after the usual introduction is to ask the pilot about his/her status - which systems are affected and what this means. It could mean that the pilot cannot deploy speedbrakes (that's trivial) or flaps (that means a long runout on the runway), or cannot perform certain manoevers (like left or right turn etc, or that the plane reacts very slow. As ATC, you should offer the nearest suitable airport and increase separation. Also a loss of hydraulic pressure can escalate quickly into a worse emergency.

Electrics failure

... means that the aircraft has very short time in the air. If all systems rely on battery, it will be drained quickly.

  • Pilots will most likely want the closest suitable airfield.
  • A major power consumer is radio communication. Consider offering solutions which need very short answers.
  • Navigational aids may fail without power. Consider vectors for routing, and monitor headings, as instruments in the cockpit might fail.
  • Expect abnormal approach procedures - shortened, steeper, but maybe with smaller bank angles - the pilot will tell what he is able to.

Smoke in Cockpit - Rauch in der Flugkanzel

Smoke in cockpit is a very challenging situation. The best way is not to lose overview in the situation. Time is critical - the aircraft has to come down really quickly. Contrary to other emergencies, smoke in cockpit means a "talk-down" approach. Supply the pilot with vectors and distance to the nearest airfield. You might consider to supply the pilot with vital information (it could be that he/she cannot see his/her instruments)in regular intervals (minutes or less), like:

Mayday Leipzig 123, speed 220 ok, altitude 6000ft ok, heading ok, runway 11 miles

Such an emergency should definitely land at the next suitable aerodrome, and maybe on a separate runway in case anything goes wrong. Increase separation considerably.

Engine Failure at takeoff - Triebwerksversagen beim Start

Engine failures are the most dangerous incidents that can happen: Altitude over ground is low, the aircraft is at full thrust and full of fuel, speed is low. This is the cocktail for a nasty situation. Most frequent reason is bird strike.

Most likely, the bird strike happened already on ground above v1, and the aircraft has to get into the air with reduced engine power. Therefore, TWR is most likely to receive the mayday call. High insecurity adds to this, as it may take time to assess the degree of damage. How much thrust is still left? Is climbing an option? Does the aircraft need to make an emergency U-turn or does it have enough time for a controlled approach?

Workload in the cockpit is very high. Quick, short response and coordination is the key to this situation. More important than in any other situation is to offer solutions, but let the pilot decide. The pilot will tell you, what he is able to and what his intentions are.

Be prepared that the aircraft may not follow the filed SID. It will most likely climb slower, step-climb and need a larger turn radius. In turns, the rate of descent might double.

Here is a perfect example, how it should work:

1. Mayday call: as precise as possible: Mayday, callsign, problem, intentions, request

Acft: Mayday mayday mayday Thomson 253H, engine failure, continuing northwesterly, inbound towards Wallasey.

2. Answer ATC: As precise as possible (listen: Thomson 253H has not requested anything, so TWR is offering the prime information which the pilot needs now): 

TWR: Thomson 253H, roger, all runways are available for landing, surface wind 070° at 5 knots.

3. ATC warns all other stations ans waits. the pilot is "in command", he will call.

Acft: Manchester, Mayday 253H

4. Pilot has called, now TWR offers solutions.

TWR: Mayday 253H, all runways are available. If you wish, vectors, or continue visually for 06 left or right.

5. Now the pilot says his intentions:

Acft: Manchester, we are heading in a northwesterly direction and trying to establish on the 85° inbound radial towards Wallacy, climb to 3500 ft and then advise you about our further intentions.

6. Manchester Tower reads back and done. If the pilot does not want anything else, then TWR keeps quiet. He knows that the pilot will fly a controlled approach via a VOR (Afterwards we will see that his right engine is dead while the left one runs normally - far enough for a modern aircraft to take off and climb). Shortly later he makes the offer to land in Liverpool - which is turned down - the pilot is happy with returning to Manchester. Then TWR reports runway 06R closed because of debris - the aircraft has lost parts of its engine. This is an order to the pilot - he should not land on a closed runway. A short time afterwards, the aircraft lands orderly on 06L.

Engine Failure at approach - Triebwerksversagen beim Landeanflug

Total engine failure

For ATC, this is easy, as it means: This aircraft will come down very quickly. In this situation, workload in the cockpit is enormous, as they try to re-light the engines. ATC's job is to analyse every option to reach ground safely and offer them in sequence of relevance.

(Very) low fuel

If fuel is gone, then this is the same situation as a complete engine failure. If such a situation is possible or even likely (=if it could happen within the distance between aircraft and airport), then the aircraft has to be routed to the nearest runway threshold. Again - the pilot decides, bearing in mind that steep turns cost altitude. If no runway can be reached, then anything like it is better than nothing - a taxiway maybe. As ATC, do not allow the aircraft to endanger other aircraft or people.

Directional Gyro Failure

The directional gyro is the "compass" of the aircraft. If the directional gyro fails, then the pilot does not know any more, where north is. Most likely, you as ATC will notice first that the aircraft goes into strange circles.

  • Normally, aircraft have a standard mechanic magnetic compass in sight - a simple ball. This is not enough to fly a vector, but good enough to fly a visual approach.
  • (it happened to me once) If the pilot has no compass (or iPhone) to look at, then the ground is the only possible visual reference. ATC can approve descent to minimum altitude until ground contact. Then, incremental turns can be issued: "turn 20° left from present heading" - until runway is in sight.

Landing gear failure

  • If landing gear fails to retract after takeoff, then this is a pan-pan situation. Crew can continue normally, but with reduced speed and more fuel consumption - crew will recalculate if they need a diversion. For ATC this means to accomodate crew's wishes.
  • A broken tyre could prevent the aircraft from retracting the gear. Landing with a flat tyre is already an emergency, as the aircraft could become unstable after touchdown. For ATC this means: Clear the runway, increase spacing behind and alert fire services.
  • If the aircraft fails to expand gear, then the situation is more critical. The only thing pilot see is their warning lights (they can't get out and see). This will occur in the last 10miles final. First reaction is a go-around to gain time to analyse the problem. In real life, the aircraft performs a low approach and technicians look at the aircraft from below. If gear fails to expand properly, then an attempted landing is imminent (at some point, the aircraf must land). This is an emergency. For ATC: Clear the runway, increace spacing behind and alert fire services.


Multiple emergencies

There is nothing more challenging than multiple emergencies, as you as controller have to rank its severity and propose measures that all of them can accomodated. If emergencies collide, you have to set priorities:

  • Aircraft which risk to go down soon have priority to those which can still fly for a few minutes (all-engine failure is first compared to hydraulics failure).
  • Aircraft which need to be on the ground first are first (passenger with heart attack is first compared to low - but not empty - fuel).
  • More people saved is better than less (full engine failure has priority compared with a passenger with heart attack).

Nothing is heavier than taking these decisions. Let's be happy to fly online.

Further reading

A [brochure by the British Air Traffic Authorities] is an excellent reference for controllers.