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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)

#141

Post by benhurmarcel »

throwaway110823 wrote: post #63
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…

Someone in my extended family works at Airbus as an engineer (hence the throwaway account) When I asked him about this accident, I brought up this specific point - the mechanical non-linkage. Sure, the Airbus is fly by wire (there are no "mechanics"), but you can still program one joystick to mimic the other joystick, right? As far as I know, the Airbus plane actually averages the inputs..?? [0] Anyway, he sorta-angr…

What would you have the system do instead of averaging the inputs? If you have 2 inputs when you should have 1, you warn with a light and sound, and what input do you use in the meantime?

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

#143

Post by braza »

whycome wrote: post #42
braza wrote: post #38

Since I started to study airline accidents, so far this one of the most fascinating in terms of human aspects and Crew Resource Management. The fact that the whole situation deteriorated less than 10 minutes after the Captain went to rest, it’s one of the biggest contrafactuals about this case.

> contrafactuals As in “if the captain didn’t go to sleep, they’d have been fine”?

Fine it’s a strong word in that context; the likelihood of the Captain and the Flying Pilot 2 make the same inputs as the FP1 it’s way reduced.

The Captain also lost the screen disagreement that happened.

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

#144

Post by bombcar »

vkou wrote: post #130
bombcar wrote: post #124

Earlier quoted context omitted.

At some point you have to have "disconnect everything, I'm going to fly this by hand" situations where the pilot can kill everyone (intentionally or no). The goal is to reduce those as far as possible, and we may be at or close to the point where any further improvements in one area cause problems in others. But I still think this particular situation could have been helped somehow . Maybe planes need emergency deplo…

A million different things would have helped in this particular situation. A stall warning that doesn't suddenly cut out when the plane exceeds a particular angle of attack [1] (That's an automation failure!). Emergency pilot tubes (That prevents the plane from dropping out of normal law!). Better pilot tubes (That prevents the plane from dropping out of normal law!) A pilot that actually received proper training (Th…

Yeah, any crash has any number of things that would have prevented it, and Airbus has had issues with the computer knowing better before (the famous airshow crash, for example: https://en.wikipedia.org/wiki/Air_France_Flight_296Q - the pilot wasn't allowed to stall the plane and it crashed; however if he HAD been allowed to stall the plane it probably would have crashed in a slightly different way).

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

#145

Post by thatswrong0 »

cedws wrote: post #126
Tronno wrote: post #98

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…

I also wonder why airspeed is derived by some formula applied to the measurement of flow along a tube that can be blocked by ice and become useless. Why not use GPS primarily and fall back to that if needed? Or the other way around even. If you expect an instrument to routinely fail, it just seems logical to at least have a backup.

Ground speed and airspeed are not the same thing. You need to measure airspeed directly. And I think there are generally 3 pitot tubes on planes.

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

#146

Post by jcalvinowens »

wkat4242 wrote: post #139
jcalvinowens wrote: post #135

Earlier quoted context omitted.

Yes. That's the only place it's mentioned, IMHO it is central to the whole thing.

It's a really long and clear paragraph, what more do you expect? The summary blames the accident on poor training and the typical EFIS "pilot out of the loop" problem, rather than very specific issues like this. Which makes very much sense IMO.

He spends a lot more time shitting on the pilot then he does talking about this, that's backwards IMHO.

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

#147

Post by orange_fritter »

psunavy03 wrote: post #64
molenzwiebel wrote: post #55

Earlier quoted context omitted.

Time and time again we learn that people do stupid things under stress. Consider Transair flight 810 [1], in which a simple engine failure during takeoff results in a complete loss of the aircraft when both pilots mistakenly identify the _wrong_ engine as malfunctioning, despite identifying the failure correctly only minutes earlier. OP has an article on that crash too, actually [2]. [1]: https://en.wikipedia.org/wik…

Another very common failure mode, and really all you can do is mandate an SOP that the crew member vocalizes which engine they're turning off, and the other crew member verifies that it's the correct engine. The other answer to "people do stupid things under stress" is the common maxim that every emergency procedure in every aircraft starts the same way. Somewhere in the cockpit is probably a standard-issue mechanica…

I see a lot of Navy pilots say "fingers and toes" to ground themselves, prevent white-knuckling, and as a "reality check". I started doing it in moments in life where I recognize that I am getting intense or lost in the moment. I've even used the phrase to calm other people down.

Random example:

https://www.linkedin.com/posts/kim-kc-campbell_a-10-pilot-re...

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

#148

Post by braza »

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…

> how many of these accidents can come down to the pilots forgetting the most basic things.

This is factually incorrect.

If you read the Final Report you will see that the FP1 (the one that have placed the abnormal inputs in the side stick) did not had the appropriate training; actually the scenario that happen has not even in the trainings (Nightly mid-atlantic flight with screen disagreement with one of the FP missing that I’m normal law).

At least for me, this accident was one of the top 3 most important in terms of safety measures and changes in aviation because the entire industry needed to think about the role of automation, training design, cockpit design, etc.

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

#149

Post by Animats »

throwaway110823 wrote: post #63
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…

Someone in my extended family works at Airbus as an engineer (hence the throwaway account) When I asked him about this accident, I brought up this specific point - the mechanical non-linkage. Sure, the Airbus is fly by wire (there are no "mechanics"), but you can still program one joystick to mimic the other joystick, right? As far as I know, the Airbus plane actually averages the inputs..?? [0] Anyway, he sorta-angr…

> When I asked him about this accident, I brought up this specific point - the mechanical non-linkage. Sure, the Airbus is fly by wire (there are no "mechanics"), but you can still program one joystick to mimic the other joystick, right?

That's come up at least twice in NTSB ship accident reports. Some ships have more than one control station. This is usually to allow driving from a control station out on a bridge wing, where the pier can be seen clearly. A high speed ferry plowed into a dock in New York City in 1993 because of confusion over which station had control. "The NTSB concludes that the propulsion control system on the Seastreak Wall Street used poorly designed visual and audible cues to communicate critical information about mode and control transfer status."[1] Big throttle levers at each station, but only the ones at one station at a time did anything. The levers did not move together.

The U.S. Navy went all the way to touch-screen throttles. After a collision involving confusion over which of three control stations was driving, they're going back to big handles.[2]

The Airbus system has been criticized, but it's two people sitting side by side. The ship systems have control stations much further apart.

[1] https://www.ntsb.gov/investigations/AccidentReports/Reports/...

[2] https://www.theverge.com/2019/8/11/20800111/us-navy-uss-john...

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

#150

Post by baby_souffle »

CoconutPilot wrote: post #107

One thing that stands out to me is the incorrect use of the word "law" when referring to flight modes. Is this just a bad translation? Are any native French speakers familiar with the Airbus documentation able to comment if the concepts make more sense in French?

> One thing that stands out to me is the incorrect use of the word "law" when referring to flight modes. Is this just a bad translation? Are any native French speakers familiar with the Airbus documentation able to comment if the concepts make more sense in French?

The word "law" can mean several things depending on the context and it's not uncommon to hear of a system following some subset of rules as operating under a certain "law".

If it's more palatable, you can `s/law/mode/g` even though you may technically have a few different possible modes under some higher "law/regime" [0]

[0] https://en.wikipedia.org/wiki/Flight_control_modes

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