You may remember Air France 447 that was en route from Rio de Janeiro to Paris on 31 May 2009 (exactly two years ago). It plunged into the ocean off the coast of Brazil. After an almost two year search, the black boxes belonging to the A330 have been found and investigated by France’s Bureau d’Enquetes et d’Analyses (BEA). I was stunned to read the reports of the situation that led to the deaths of 228 people
Flight Global has the blow by blow final six minutes of the flight. In summary what happened was this:
- The aircraft pitot tubes (used to determine the airspeed of an aircraft) failed and began giving false/inconsistent readings (as has always been suspected and why airlines have been replacing this type of pitot tube). The false reading was for less than a minute.
- the autopilot and autothrust disengaged. This is undoubtedly because of the false data. As one commentator described it, at this point the plane is now similar to a Windows PC in “fail safe” mode. Some key safety features are shut down at this point
- The plane began to roll to the right and the Pilot “appears to have rolled the aircraft to the left, to counter the roll to the right, he also pulled the aircraft’s nose upwards – for reasons yet to be explained (flight global) and the plane climbed to 38,000 ft. The normal safety systems would not allow this to happen but they had been automatically Shut down
- the stall warning was triggered and the plane stalled (BEA) but„ the inputs made by the PF were mainly nose-up (BEA). In other words, the pilot kept trying to take the plane up but “The A330’s angle of attack is too high, and the aircraft is losing the battle to sustain lift, as demonstrated by the stall alarm, yet the pilot is still keeping the nose pointing upwards – in apparent contradiction to a basic principle of flight: escaping a stall requires the nose to be pushed down, in order to regain a smooth, fast airflow over the wings.”
- The engines are taken to full power but the resulting thrust is not enough for the heavy aircraft to have enough lift in the thin air at that altitude
- the plane then reached an angle of over 35 degrees (probably close to 40 degrees)
- The plane then dropped 38 000 feet (11.6km, 7 miles) in 3 min 30 secs (can you imagine how terrifying that would be to be falling a mile every 15 seconds). During this time, the A330 remained stalled. It hit the water at 200km/h
On Air France 447, all three pilots were all very experienced. Why did they commit such a mistake? And what would stop another experienced crew making the same mistake.
Three helpful links to help reflect on this crash:
- Brett Snyder (Cranky Flier) has a very useful commentary on the situation in which he expresses concern about the pilot errors that caused the plane to crash
- Clive Irving in a Daily Beast news article on Flight 447’s Terrifying Four and a Half Minute Crash notes what I have been wondering: ” there must be critical attention paid to those faulty speed gauges. Indeed, attention should return to a report on the crash by the BEA released in November 2009. Buried in the technical details was the revelation that there was a record of at least 53 instances in which flight crews had faced control problems directly caused by the speed gauges and “13 significant events involving five airlines operating A330/340 airplanes.” Airbus itself reported 32 incidents between 2003 and 2009 that were attributable “to the possible destruction of at least two gauges by ice.”
- Plane crash info which gives you information on what causes plane crashes and why you should avoid commuter airlines! Pilot error represents 50% of all accidents and commuter lines generally use way less experienced pilots. The accident rate for fatalities per million hours is almost three times greater for commuter flights than for regular mainline airlines.