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The crash of Air France flight 447 (2021)

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Re: The crash of Air France flight 447 (2021)

#91

Post by jcalvinowens »

The article misses the key takeaway from this incident IMHO.

When the controls were pegged at full aft deflection, the stall warning would cease, because instrument readings in the deep stall were considered invalid by the computer. Whenever the pilot would start to push forward to recover, the computer stopped rejecting the readings, and started sounding the stall warning again!

So every time the pilot started to do the right thing, the airplane would start screaming "STALL STALL" at him, and he would pull the stick back again to make it stop.

I firmly believe that they would still be alive if the stall warning had either not been installed at all, or had functioned properly.

Re: The crash of Air France flight 447 (2021)

#92

Post by mrguyorama »

dabluecaboose wrote: post #60
t0mas88 wrote: post #25

Earlier quoted context omitted.

In normal law an Airbus doesn't stall with full back stick, that would just result in maximum AoA not a stall. In this case it had degraded to loose some of those protections due to icing of the sensors. That was confusing to the junior co-pilot, and they skipped basic procedures on who has control resulting in opposite inputs and a loss of control.

Yeah, I guess as someone who's had minimal instruction it seemed obvious. But reading the article it's clear that the junior FO was trained basically exclusively on the fly-by-wire Airbuses and probably didn't have that intuitive understanding when that protection was stripped away.

The plane in this case doesn't matter. No training for stalls ever tells you to pull up. It's directly opposed to how stalls ARE trained. This pilot was a chaos monkey, and the other pilots were unable or unwilling to get the chaos monkey out of the situation. He had completely reverted to human instinct, which is terrible for flying, and also was letting himself override his copilot, who was handling the situation much better.

People act like this situation wouldn't have happened had they had boeing style connected controls, but it's pretty likely that in this state, Bonin would have actively been wrestling with the controls to point the nose up in that state too. The only way to keep Bonin from killing everyone would have been to restrain him. There is no reliable way to "knock" someone out of that kind of panic state.

Re: The crash of Air France flight 447 (2021)

#93

Post by brazzy »

kloch wrote: post #52

It's tempting to blame the inexperienced first officers, their training, or the CRM failures on this flight, but the blame for this crash has to land squarely on the atrociously bad UX of the Airbus cockpit. Sensory overload and no clear readout of what is actually broken (pitot tube icing in this case) is bad but the fly-by-wire joystick configuration is what really doomed this flight. In Boeing airliners and many o…

>It's tempting to blame the inexperienced first officers, their training, or the CRM failures on this flight, but the blame for this crash has to land squarely on the atrociously bad UX of the Airbus cockpit.

Hard disagree. No matter how bad the UX, there just isn't any conceivable situation where Bonin's pulling up the rudder for minutes on end wasn't suicidally dangerous, or made any sense at all.

Re: The crash of Air France flight 447 (2021)

#94

Post by mrguyorama »

TillE wrote: post #31
jmyeet wrote: post #2

It's kind of amazing how many of these accidents can come down to the pilots forgetting the most basic things. In this case, ultimately, the pilot and the co-pilot were exerting opposite controls. One to pull up, one to push the nose down. In a stall you push the nose down to gain aerodynamic lift. That's like Flying 101. But I guess when you panic, the natural instinct of wanting to pull up kicks in when you're rapi…

Yeah the "insane pilot error" crashes always get me. American 587 is another example where, in response to normal wake turbulence, the pilot mashed the rudder back and forth so hard it broke the stabilizer.

The pilot in that case was essentially taught that doing so was an acceptable thing.

Re: The crash of Air France flight 447 (2021)

#95

Post by zerocrates »

jcalvinowens wrote: post #91

The article misses the key takeaway from this incident IMHO. When the controls were pegged at full aft deflection, the stall warning would cease , because instrument readings in the deep stall were considered invalid by the computer. Whenever the pilot would start to push forward to recover, the computer stopped rejecting the readings, and started sounding the stall warning again! So every time the pilot started to d…

This is mentioned in the article.

Re: The crash of Air France flight 447 (2021)

#96

Post by _cenw »

bombcar wrote: post #83
t0mas88 wrote: post #20

Earlier quoted context omitted.

It has been changed after this incident. There is now an alert for dual input. The resulting Airbus system is better than traditional connected yokes, because it doesn't have the unexpected opposite input anymore (with the alert) but it does also have an override switch for the captain's side. Which means you can overpower the first officer with just a button instead of physically having to wrestle for the controls.…

Of course that introduces the problem of "what if the captain is the startled pilot" - can the first office override the captain?

Yes, but whoever hits the button last gets control, so you can take priority back.

(Unless you manage to hit the priority button for 40 seconds - but I assume that's for locking out a broken stick that's doing inputs at rest)

Re: The crash of Air France flight 447 (2021)

#97

Post by _cenw »

jcalvinowens wrote: post #91

The article misses the key takeaway from this incident IMHO. When the controls were pegged at full aft deflection, the stall warning would cease , because instrument readings in the deep stall were considered invalid by the computer. Whenever the pilot would start to push forward to recover, the computer stopped rejecting the readings, and started sounding the stall warning again! So every time the pilot started to d…

It's important to note the stall indication itself wasn't disregarded, but the indicated airspeed (that is a prerequisite). This plane was in the exceptional situation of falling out of the sky faster than it was moving forward.

Re: The crash of Air France flight 447 (2021)

#98

Post by Tronno »

In post-mortems involving pilot error, what strikes me is that airliner cockpit design sounds so convoluted, unintuitive, and just plain bad. The burden of disentangling this bad design is always placed on the pilots - through extensive training and rote memorization - which inevitably fails under stress.

In this particular example, consider:

- the opposing pilot inputs being signaled only by a pair of little green lights

- the cacophony of warning lights and alarms which, together, say little more than "something is wrong"

- instruments that direct a pilot to pull up during a full stall

- sensor failures with no clear indicator

- computer safeguards suddenly removed without a stated reason

Etc. And the expectation towards the crew is to quickly and corrently reason about this stream of conflicting signals, while embroiled in a sudden emergency.

It smacks of pure engineer-driven design, assembled with serious attention to the technical issues, but with near-zero empathy for the humans who will be operating the contraption.

Reminds me of internal web tools at so many companies. They present giant messy forms, with checkboxes and dropdowns for every conceivable edge case, which have to be manipulated just so or the system explodes. And when something breaks, of course it's the user's fault every time.

Re: The crash of Air France flight 447 (2021)

#99

Post by jandrese »

psunavy03 wrote: post #46

I fly a desk herding cats, I mean devs, for a living now. But as a Navy-trained aviator, this and the Colgan Air mishap in Buffalo always make me cringe. I can't entirely judge the crew, because the human mind is a strange thing that has ways of rationalizing truly abnormal situations and behavior. That said, an obvious Crew Resource Management failure compounded the issues here. That said, I believe aerobatics and o…

Maybe not even acrobatic flying training but glider training. Pilots with glider experience are some of the best performers in emergencies.

Re: The crash of Air France flight 447 (2021)

#100

Post by eastbound »

afterburner wrote: post #86
eastbound wrote: post #70

Earlier quoted context omitted.

Armchair amateur, Pitot tube failure is such a frequent occurrence that I’m angry we display any other warning than this one. - It should have a needle to eject caps on it, so that pilots don’t forget the caps (Brisbane accident, among many), - The needle should also sense, if not remove, the ice (Air France accident), - It should wake up the pilots and reset controls to fixed values for the current altitude, since w…

Pitot tube failures are incredibly frustrating. In one case it's theorized a wasp nest blocked the inside of one, after not being covered while on the ground a long time. https://en.wikipedia.org/wiki/Birgenair_Flight_301

They seem so close to the cockpit window that it’s frustrating pilots can’t open the window (which they can, but not in flight) and clean it up.
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