For more than two years, the disappearance of Air France Flight 447 over the mid-Atlantic in the early hours of June 1, 2009, remained one of aviation’s great mysteries. How could a technologically state-of-the art airliner simply vanish?
With the wreckage and flight-data recorders lost beneath two miles of ocean, experts were forced to speculate using the only data available: a cryptic set of communications beamed automatically from the aircraft to the airline’s maintenance center in France. The data implied that the plane had fallen afoul of a technical problem – the icing up of air-speed sensors – which in conjunction with severe weather led to a complex “error chain” that ended in a crash and the loss of 228 lives.
The matter might have rested there, were it not for the remarkable recovery of AF447′s black boxes this past April. Upon the analysis of their contents, the French accident investigation authority, the BEA, released a report in July that to a large extent verified the initial suppositions.
Back in October, we ran a story based on the findings of a book called Rio-Paris Crash: A Collection of Pilot Errors, written by French aviation author Jean-Pierre Otelli. This described a scene in the Airbus cockpit that was dominated by confusion, a lack of co-ordination, and denial among the flight crew as they struggled to deal with a stall.
An even more detailed picture has emerged with the publication of a new book entitled Erreurs de Pilotage (volume 5), also written by Jean-Pierre Otelli, which includes the full transcript of the pilots’ conversation.
We now understand that, indeed, AF447 passed into clouds associated with a large system of thunderstorms, its speed sensors became iced over, and the autopilot disengaged. In the ensuing confusion, the pilots lost control of the airplane because they reacted incorrectly to the loss of instrumentation and then seemed unable to comprehend the nature of the problems they had caused. Neither weather nor malfunction doomed AF447, nor a complex chain of error, but a simple but persistent mistake on the part of one of the pilots.
Human judgments, of course, are never made in a vacuum. Pilots are part of a complex system that can either increase or reduce the probability that they will make a mistake. After this accident, the million-dollar question is whether training, instrumentation, and cockpit procedures can be modified all around the world so that no one will ever make this mistake again – or whether the inclusion of the human element will always entail the possibility of a catastrophic outcome.
After all, the men who crashed AF447 were three highly trained pilots flying for one of the most prestigious fleets in the world. If they could fly a perfectly good plane into the ocean, then what airline could plausibly say, “Our pilots would never do that”?
Jeff Wise, writing for Popular Mechanics magazine has published an extremely detailed…and slightly disturbing synopsis of what occurred during the course of the doomed airliner’s final few minutes…
At 1h 36m, the flight enters the outer extremities of a tropical storm system. Unlike other planes’ crews flying through the region, AF447′s flight crew has not changed the route to avoid the worst of the storms. The outside temperature is much warmer than forecast, preventing the still fuel-heavy aircraft from flying higher to avoid the effects of the weather. Instead, it ploughs into a layer of clouds.
At 1h51m, the cockpit becomes illuminated by a strange electrical phenomenon. The co-pilot in the right-hand seat, an inexperienced 32-year-old named Pierre-Cédric Bonin, asks, “What’s that?” The captain, Marc Dubois, a veteran with more than 11,000 hours of flight time, tells him it is St. Elmo’s fire, a phenomenon often found with thunderstorms at these latitudes.
At approximately 2 am, the other co-pilot, David Robert, returns to the cockpit after a rest break. At 37, Robert is both older and more experienced than Bonin, with more than double his colleague’s total flight hours. The head pilot gets up and gives him the left-hand seat. Despite the gap in seniority and experience, the captain leaves Bonin in charge of the controls.
At 2:02 am, the captain leaves the flight deck to take a nap. Within 15 minutes, everyone aboard the plane will be dead.
02:03:44 (Bonin) La convergence inter tropicale… voilà, là on est dedans, entre ‘Salpu’ et ‘Tasil.’ Et puis, voilà, on est en plein dedans…
The inter-tropical convergence… look, we’re in it, between ‘Salpu’ and ‘Tasil.’ And then, look, we’re right in it…
The intertropical convergence, or ITC, is an area of consistently severe weather near the equator. As is often the case, it has spawned a string of very large thunderstorms, some of which stretch into the stratosphere. Unlike some of the other planes’s crews flying in the region this evening, the crew of AF447 has not studied the pattern of storms and requested a divergence around the area of most intense activity. (Salpu and Tasil are two air-traffic-position reporting points.)
02:05:55 (Robert) Oui, on va les appeler derrière… pour leur dire quand même parce que…
Yes, let’s call them in the back, to let them know…
Robert pushes the call button.
02:05:59 (flight attendant, heard on the intercom) Oui? Marilyn.
02:06:04 (Bonin) Oui, Marilyn, c’est Pierre devant… Dis-moi, dans deux minutes, on devrait attaquer une zone où ça devrait bouger un peu plus que maintenant. Il faudrait vous méfier là.
Yes, Marilyn, it’s Pierre up front… Listen, in 2 minutes, we’re going to be getting into an area where things are going to be moving around a little bit more than now. You’ll want to take care.
02:06:13 (flight attendant) D’accord, on s’assoit alors?
Okay, we should sit down then?
02:06:15 (Bonin) Bon, je pense que ce serait pas mal… tu préviens les copains!
Well, I think that’s not a bad idea. Give your friends a heads-up.
02:06:18 (flight attendant) Ouais, OK, j’appelle les autres derrière. Merci beaucoup.
Yeah, okay, I’ll tell the others in the back. Thanks a lot.
02:06:19 (Bonin) Mais je te rappelle dès qu’on est sorti de là.
I’ll call you back as soon as we’re out of it.