That is the real danger: this faulty reaction to the stall, rather than the stall itself. It is quite rare that a pilot is killed simply because he stalled. But it happens with tragic monotony that a pilot is killed because he either fails to recognize the stall for what it is, or fails to control that impulsive desire to haul back on the stick.
– Wolfgang Langewiesche
I am disappointed at how pilots get very defensive over Air France 447. Pilots who have never flown a stall even in primary training insist they are well-trained, and that this could never happen to them.
It’s like we are talking about different accidents altogether.
AF447 stalled and fell, truly out of control, for nearly 4 minutes. During nearly all of those 4 minutes, the stall warning alarms never stopped. A synthetic voice called out “Stall, Stall, Stall!” and an irritating ‘cricket’ rattled loudly. The pilots inexplicably ignored those warnings the entire time, and experimented with various control inputs with increasing befuddlement.
Every student pilot knows that there is only one correct control input sequence for stall recovery.
An Airbus pilot wrote on PPRUNE that the A330 is not certified for stalls, so they don’t practice stalls. And simulators don’t replicate stalls well, so pilots train only up to stick-shaker, the initial onset of a stall. They train for prevention, not recovery. It’s like training to ski by standing at the top of the slope, then going home.
Two key facts stand out:
1. The pitot ice lasted less than a minute. After that, the crew had all the information they needed to fly the airplane normally.
2. The airplane was flying normally when the autopilot disconnected. The airplane flew normally until the crew intervened with aft stick.
Yes, there was an initial instrument fault. But an airplane flying at a normal 500 knots is still flying at 500 knots even if the airspeed indicator stops. If the pilots sat on their hands and reflected for a few moments, they would be alive today.
But the youngest of the pilots pulled the airplane into a steep climb. He held the stick back nearly the entire time. He never mentioned what he was doing.
The article calls out a key point:
3. The A330′s control systems are asynchronous.
The side sticks on an Airbus are “asynchronous”— they move independently. “If the person in the right seat is pulling back on the joystick, the person in the left seat doesn’t feel it,” says Dr. David Esser, a professor of aeronautical science at Embry-Riddle Aeronautical University. Robert [the PNF] has no idea that Bonin [the PF] has continued to pull back on the side stick.
From his [jump]seat, Dubois [the Captain] is unable to infer from the instrument displays in front of him why the plane is behaving as it is. The critical missing piece of information: someone has been holding the controls all the way back for virtually the entire time. No one has told Dubois, and he hasn’t thought to ask.
The article leaves no doubt as to what the immediate cause of the crash was.
02:10:55 (Robert) Putain!
The cockpit’s avionics are now all functioning normally. The flight crew has all the information that they need to fly safely, and all the systems are fully functional. The problems that occur from this point forward are entirely due to human error.
If Bonin were to let go of the controls, the nose would fall and the plane would regain forward speed. But because he is holding the stick all the way back, the nose remains high and the plane has barely enough forward speed for the controls to be effective. As turbulence continues to buffet the plane, it is nearly impossible to keep the wings level.
It is not until 3 minutes and 33 seconds after the stall warning that the pilot flying, Bonin, finally reveals what he has been doing:
02:13:40 (Robert) Remonte… remonte… remonte… remonte…
Climb… climb… climb… climb…
02:13:40 (Bonin) Mais je suis à fond à cabrer depuis tout à l’heure!
But I’ve had the stick back the whole time!
At last, Bonin tells the others the crucial fact whose import he has so grievously failed to understand himself.
02:13:42 (Captain) Non, non, non… Ne remonte pas… non, non.
No, no, no… Don’t climb… no, no.
Just 48 seconds after the Captain finally realized what Bonin was doing, the aircraft hit the South Atlantic, and everyone died.
Third on my list of illustrative accidents was the fatal crash of a flying school’s Cessna 152. The instructor and his student made a low pass over my home airfield. Fellow members at Angeles City Flying Club told me that the airplane flew a low approach over runway 08, then pitched up steeply at the departure end. The left wing dropped, and the airplane yawed and rolled left to a vertical dive, just as power came back on.
The crash, a few meters north of the runway fence, was catastrophic and non-survivable. The instructor pilot was well-liked and respected by his peers.
I don’t know where the investigation is on that one. The crash site, beside our runway, is a macabre reminder to me that lessons are yet to be learned to give some meaning to that loss.
Then there was another crash. This one was captured on video.
Posted from Manila, December 30, 2011.