December 08, 2011
What Really Happened Aboard Air France 447
Jeff Wise in Popular Mechanics:
With the wreckage and flight-data recorders lost beneath 2 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. As PM found in our cover story about the crash, published two years ago this month, 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. An even fuller picture emerged with the publication of a book in French entitled Erreurs de Pilotage (volume 5), by pilot and aviation writer 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.
More here. [Thanks to Margit Oberrauch.]
Posted by Abbas Raza at 11:56 AM | Permalink
Comments
This is really chilling. pitot tube icing may have triggered these events, but it was clearly pilot error that killed those people. One of the first lessons I learned in pilot training was to push forward in the event of a stall, not pull back!
Posted by: Reader | Dec 8, 2011 12:27:02 PM
Horrible.
Painful reading.
I imagine this will be obligatory homework for pilots in years to come.
Posted by: John Ballard | Dec 8, 2011 5:42:55 PM
Of course it is easy to be a Monday morning quarterback and second guess decisions made by experienced pilots under time and other pressures. However, I think one point is clear. The senior pilot Marc DuBois was clearly negligent in several ways. First, he had not directed and planned an alternate course out of the bad weather area. Second, he left the two more inexperienced pilots in charge with no directions of what to do in an emergency or how to raise him up to speed quickly if necessary. He showed his callous disregard for the safety of everyone by leaving the flight deck for a “nap” or whatever he may have been doing.
Obviously the Captain, with the many thousands of flight hours experience, knew, or should have known, the potential of this weather situation for a serious problem. It is very likely that if he had remained at the controls, this plane would not have crashed in such a horrible and tragic manner. After all, it is situations like this where the experienced captain is most needed, not when everything is going well. A significant part of the training of junior pilots is to observe the senior pilot react to situations like this, but not be themselves trusted to make those decisions. Even if the Captain had remained in the flight deck, the flight likely would have been saved because he would have observed and had knowledge of the error of the junior pilot in control. By the time he got there and became appraised of the situation, it was too late.
Long before my sixteenth birthday, before I had a driver’s license, my Father would let me steer our 1938 Chevrolet sitting next to him. I graduated to more complicated things like shifting the floor gear shift and learning the pattern. He only did this within a few blocks of home or in a very rural area with almost no traffic and good weather conditions to avoid risk of an accident. He was still sitting in the driver’s seat ready to respond to any emergency which might develop. Only later would he allow me to sit in the driver’s seat and operate the clutch, brake, accelerator pedal and shift the transmission and steer the vehicle. But he carefully monitored all my actions and was ready to react if an emergency developed. None ever did but it could have. He constantly cautioned me both verbally and by his own actions when driving, to drive in a defensive way and be prepared to stop or avoid an accident on short notice. Stop, Look and Listen.
Regardless of the complicated dual control by manual pilots and computer systems, or freezing up of sensors, clearly the senior pilot failed in his duties as this excellent article shows. Yes, the junior pilots technically caused the failure, but only because the senior pilot was napping and failed to chart a course around this bad weather in the first place.
Posted by: WJAbbe | Dec 8, 2011 5:53:04 PM
WJAbbe,
I can't agree with you. All pilots are trained to move the control stick forward in the event of a stall to put the nose down and regain airspeed. The pilot who continued to do the opposite of this bears by far the most responsibility for this tragedy. In addition, the airline bears responsibility for very inadequate training in manual piloting. These are basic skills that seem to have been forgotten in the fly by wire airliner. All it took was some frozen pitot tubes to compromise all this advanced technology. I only hope that pilots are now properly trained for these situations.
Posted by: Reader | Dec 8, 2011 7:37:59 PM
It was bizarre to me that the plane was averaging the commands of its two copilots in deciding what to do. I can see overriding one set of instructions with another, but why on earth would you design a system to accept "speed up and go left" and "slow down and go up" and decide to stay at roughly the same speed, go slightly up and slightly left? What's a good reason to do this thing?
Posted by: prasad | Dec 9, 2011 9:35:12 AM
Yes, the junior pilots technically caused the failure, but only because the senior pilot was napping and failed to chart a course around this bad weather in the first place.
I can't agree. Irregardless of whether they should have routed around the weather, given they did stall, the pilots simply did not do what they were (supposed to be) trained to do. Even a junior pilot is supposed to know all about stall recovery. The only reason pilots are still needed in the first place is to handle emergencies, otherwise we could replace them with software and remote piloting uplinks and save ourselves a lot of money.
Posted by: Jason | Dec 10, 2011 4:52:25 AM
For what it's worth, one of the introductory tutorials on the Microsoft Flight Simulator video game tells you about low air pressure, stalling, and the need to pitch the nose forward when you stall to pull out of it. This is literally one of the first things you learn when you're playing a video game about flying. It's completely bizarre that these pilots, who must have had thousands of flight hours under their belts, wouldn't have corrected the stall, especially since the computer was screaming "STALL" at them over and over.
Posted by: Joe | Dec 10, 2011 1:02:41 PM
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