One of air travelers’ worst fears is engine failure! What happens if an engine breaks down or catches fire? How are pilots dealing with the situation? We’ll try to explain it all here.
Engine failure is highly unlikely
Without going into complex technical explanations that would be beyond our remit, you should know that the risk of engine failure is virtually nil.
As the blog Peur Avion (Plane Fear), which is well versed in aviation safety issues, wrote, the probability of a Boeing 767 experiencing such a failure is one in 4,000,000,000 flight hours (four billion)! And we’re talking about figures from over 20 years ago, while each generation of aircraft and engine makes significant progress in this area.
According to the same source, “Research carried out by a team from ESTACA has proved that the failure rate on a twin-engine aircraft is only 0.00000236, even when all conceivable cases are taken into account, from volcanic ash to human handling errors!
We’ve all heard about the crash on the Hudson due to bird ingestion, but this kind of phenomenon happens 30,000 times a year without causing the slightest problem!
While cases of aircraft engine failure are highly publicized, they are very rare. Today, it’s accepted that a pilot can go his whole career without experiencing one, so as a passenger, the risk of encountering one is virtually nil.
Engine failure? No big deal!
But let’s assume that you’re really unlucky (you’re 35,000 times more likely to win the Euromillion jackpot than to suffer such a breakdown) and that your flight has an engine failure. Is it serious?
Not all failures are created equal. It all depends on when it happens (cruising, during take-off…), where it happens (in the middle of the ocean, near an airport), how it manifests itself (engine shut down or in flames) and how many engines are affected…
If losing one engine is rare, losing two is even rarer, let alone four if you’re flying a B747 or A380!
Depending on the model, a commercial aircraft can fly for “a certain amount of time” with a single engine. That’s the whole point of ETOPS certification, which tells us how long an aircraft can fly on a single engine, and determines the maximum distance it must stay from an airport to land in an emergency. Today’s most modern aircraft are certified to last up to 7 hours on a single engine, almost an Atlantic crossing.
And just because engine failure is highly unlikely, don’t pretend it doesn’t exist. Aircraft and engines are regularly overhauled and sometimes completely dismantled during major maintenance visits. As for the pilots, while the risk of such a failure is virtually nil in flight, they are constantly confronted with it in simulators and are perfectly trained to handle such situations.
So you’re still convinced that you’re at risk of engine failure on your next flight? We’ll explain what’s going on and how it’s being handled.
We’ll look at two cases: engine failure on take-off and in flight.
NB: this is a popularization article for the general public, which does not claim to be as exhaustive and precise as what a pilot would explain to you!
What to do in the event of an engine failure on take-off?
Take-off is the most critical phase of the flight. The aircraft takes off on the runway and, depending on the speed it reaches, is either not yet able to take off, or is no longer able to stop, with a grey zone where it can no longer stop, but where taking off requires the utmost precaution.
As the aircraft gains speed, it will reach three levels.
- V1: this is the speed at which, for the last time, the pilot can decide not to take off. Once V1 is exceeded, takeoff will take place, no matter what happens. In practice, given the reaction time between the occurrence of an event and the pilot’s reaction, if a decision is taken at V1 or even just before, the reaction will take place when it has been exceeded. So it’s really a critical moment when the driver has to make the right decision.
- Vr: rotation speed, the speed at which the pilot can raise the nose of the aircraft towards the sky (nose-up) to get it airborne. This is a minimum speed: at Vr, the pilot must carefully raise the nose, as the speed may be “just enough”; when the aircraft is going faster, he can maneuver more directly.
- V2: this is the safety speed at which the aircraft can take off in the event of an engine failure.
V1, Vr and V2 are calculated for each takeoff, depending on the aircraft, its load, weather conditions, etc.
Under normal conditions, an aircraft accelerates to Vr and rotates after Vr. In the event of engine failure, it will either wait until V2 has been reached to rotate, or V2 must be reached within 15m of the ground.
So back to our engine failure.
If it is identified and the pilot acts before V1, the pilot aborts the take-off procedure (RTO: Rejected Take Off). He extends the flaps, engages the thrust reversers and applies the brakes. In practice, as soon as the thrust reverser is engaged, the autobrakes are activated to ensure optimum braking without pilot action, leaving the pilot free to concentrate on other parameters such as the aircraft’s trajectory.
Here’s a Rejected Take Off exercise on an A330 Neo.
If the fault is detected after V1 or if the pilot reacts after V1 :
1°) The pilot will try to keep the aircraft on course by compensating for the thrust of the failing engine. This exercise usually enables him to determine which engine is faulty, if he hasn’t already done so.
2°) At Vr he will pitch up the aircraft. The aim is to leave the ground at V2, or to reach V2 no later than 15m from the ground, so as to have sufficient speed to climb safely on a single engine without stalling. The pitch-up will be more gradual than under normal conditions, to give the aircraft time to reach V2.
3°) Once a sufficient climb rate has been reached, the crew can analyze the situation and, if necessary, engage the autopilot to concentrate on the checklist. The pilot must compensate for asymmetric thrust.
4°) The malfunctioning engine is switched off. It’s worth remembering that you need to switch off the right engine! Everyone remembers the crash of the ATR in Taipei, when the crew cut the wrong engine while in full ascent.
Then it all depends on what is found, but unless other urgent measures need to be taken, the crew will contact the control tower to assess the best option, which may be a return to the airport or a landing at a more easily accessible nearby airport.
What to do in the event of an in-flight engine failure?
Second scenario, just as improbable as the first: in-flight failure.
It may seem obvious, but the pilot’s first priority is to keep the plane flying. With one engine out, it can’t maintain both speed and cruising altitude, so it’s going to have to arbitrate, and common sense dictates that it will have to descend to maintain a speed that will avoid stalling.
In theory, all this work will be done by the on-board computer, which will determine the optimum attitude.
Once this altitude has been determined and entered into the autopilot, the pilot moves on to the next step.
Then he’ll communicate with air traffic control. As in the case of an engine failure during takeoff, the pilot’s first priority is to ensure that the aircraft is flying in the best possible conditions (altitude, speed, trajectory) and to solve any urgent problems before communicating! To be more precise, the pilot handles maneuvers while the co-pilot handles communications.
Air traffic control will be informed of the situation and any decisions taken.
Only then is a diagnosis made! Once again, the priority is to get the aircraft flying in the best possible conditions, and nothing that diverts the crew’s attention from this objective should be undertaken until the aircraft is “safe”. Here again, the pilot maneuvers while the co-pilot handles the checklist. And the first action taken is to shut down the faulty engine.
Once the problem has been fully analyzed, it’s time to make some calm decisions. Once again, it all depends on the context, the aircraft… It may be decided to fly to the nearest airport, but remember that a twin-engine jet can sometimes fly for up to 7 hours on a single engine!
And what about the passenger?
In the unlikely event of such a scenario, the crew is fully trained to deal with it calmly.
But there’s no guarantee that passengers will experience it in the same way! Seeing an aircraft change trajectory, reduce speed and altitude in mid-flight is worrying, especially if it’s accompanied by a strange noise or even flames!
Passengers will of course be informed as soon as the situation allows! But it’s understandable that, for safety reasons, the crew’s priorities are in this order: flying the aircraft, solving problems, communicating with the outside world, informing passengers.
Bottom line
Engine failure is one of the greatest fears of passengers, but if it is widely publicized or even exaggerated by the media, it is more than unlikely.
But even then, crews are fully trained to handle them, and remember, modern aircraft can fly on a single engine for hours.
Photo :frankpeters / iStock
