From bird strike to emergency plane evacuation – Decision making illustrated
A few days after the Qantas Boeing 747 in flight depressurization, another incident retained my attention, because it’s really a typical illustration how hard decision making can be. An AirMauritius Airbus 330 was hit by a bird while it was rolling for take-off.
The crew decided to abort the take-off, and applied full brakes to get the airplane to a stop. This resulted in brakes over-heating, and one of the tires caught fire. The fire brigade intervened quickly, but the plane was evacuated using the emergency slides.
Can you imagine how quick that situation evolved ? The guys were having a normal take-off, approaching V1 (the speed above which take-off is no longer an option), when the plane hits a bird ! They aborted the take-off, and then got a break overheat alarm, probably followed by a fire alarm. The time between the start of take-off and the end of the evacuation was probably less than four minutes.
So close to take-off, there are only seconds to make a decision, and this is exactly why V1 is for. Should anything occur at a speed bleow V1, the crew aborts the take-off. This is easy when the event is a technical alarm, but if the problem is a sound or a strange vibration, things are much complex. It’s not obvious that both pilot will hear / feel / smell it, and they have to find a common understanding, which can take long seconds, possibly leading to a speed above V1, and to a take-off with a serious doubt…
The rule when flying single engine aircraft is much easier: any problem on the ground stays on the ground. But when the runway is short, and the speed is already high, a non-engine problem sometimes has to come in the air. To make good decisions in such critical moments, a detailled knowledge of the aircraft and its systems is of paramount importance.
The AirMauritius crew certainly knew about the inherent risks associated to an high-speed take-off abortion. Given the huge amount of energy to be dissipated by the braking system, its temperature rises super quickly. Even after low-speed aborted take-off, and visual inspection by the fire brigade is part of the standard procedures.
The picture below ( (c) Tom Philip, via airliners.net) shows how big an A330 landing gear is. The braking system is located within the white discs seen within the main gear assembly. The people standing by the landing gear give a good reference how large the tires are…
You can now better imagine the heat required to start a fire in such a tire, but also the risk that a burning tire represent to the aircraft it belongs to. In the AirMauritius case it is clear that the fire was caused by the aborted take-off.
Was the decision to abort a good one ? It’s hard to comment about it, mostly because no anoucement was made regarding where the bird did hit the plane. Windshield or engine are certainly the most critical parts, but bird strike on the wings or control surfaces can also have serious impacts.
Even if the plane had to get evacuated, it did not suffered major damages, and all passengers are well. On that basis, one can say that the crew made a good job. Could the abortion have been managed another way, or the fire brigade intervention have been more efficient ? One is always smarter after an incident…
I’m looking forward to the conclusion of the investigation, and to the possible recommendations that will be issued. As always, anything that will be said before will be pure speculation, and shall be disregarded.
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One Comment, Comment or Ping
sylvia
That’s a difficult one – I’d not heard about this but I too am interested to hear what the investigation comes up with.
Aug 8th, 2008
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