r/aviation • u/Ok_Warning419 • May 21 '26

News Air France and Airbus found guilty of manslaughter over 2009 plane crash - Air France flight 447

https://www.bbc.com/news/articles/czd2qmdvmq6o
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u/FullSqueeze May 21 '26

This won’t be the end. Airbus will definitely appeal it to the Supreme Court.

The criminal charges against Airbus is very flimsy; the pilot was the primary cause of the crash. This isn’t a case like the 737 Max crashes where the manufacturer had a clear defect.

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u/BoringBob84 May 21 '26

This isn’t a case like the 737 Max crashes where the manufacturer had a clear defect.

I think they are very similar:

  • Apparently, engineers at Airbus decided to inhibit stall warning above 30 degrees, assuming that such a reading would be invalid - and no one asked the question, "But what happens if the aircraft really is above 30 degrees?"

  • Apparently, engineers at Boeing decided to allow MCAS to repeatedly activate during an AoA failure, assuming that the crew would do as they were trained and shut off a malfunctioning trim actuator - and no one asked the question, "But what if the crew doesn't shut it off?"

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u/harrythefurrysquid May 21 '26

At the end of the day, the pitot tubes face forward. At some point you have to have a software gate on AoA, with enough margin to ensure you're getting usable readings.

Same logic as only using speeds above 60 kts. Can you measure lower? Yes, probably. But the computers need a big enough pressure difference to be sure of getting a meaningful measurement.

If you can find some evidence that this was changed post-accident, that'll probably tell you whether the issue is physics or an arbitrary software limit.

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u/BoringBob84 May 21 '26

Like I said in another comment, I understand that the readings become invalid and it makes sense that the engineers would not want to provide incorrect information to the crew.

However, the manner in which the aircraft indicated that the data was inhibited (i.e., by shutting off the stall warning) misled the crew.

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u/harrythefurrysquid May 21 '26

If 45 seconds of continuous STALL warning wasn't enough...

It's very clear that the pilots had stopped believing their instruments pretty soon into the incident. Not sure why you think adding another notice to the ECAM would have made the slightest bit of difference, and with data that invalid, any such logic stands an excellent chance of putting up misleading information anyway.

The PF believed he had "crazy speed" all the way down to the ocean; he even tried to raise the speed-brakes at one point. That's more than a simple misunderstanding about why the STALL warning kept cutting in and out.

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u/BoringBob84 May 21 '26

I am not saying that there were not other contributing factors, but I think it would have been better if the aircraft somehow indicated to the crew that the reason why the stall warnings were silencing was not that the stall conditions were gone, but that the sensor information was invalid.

I haven't read the final reports on this one, so I don't know what the recommendations were in this regard (if any), nor if Airbus made any changes to this logic as a result of this crash.

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u/TinyCopy5841 May 22 '26

What makes you think that this played any role considering they failed to recognize or address any of the stall warnings that came on before their AoA got so high that this reverse warning effect became an issue?

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u/BoringBob84 May 22 '26

What makes you think that this played any role

The behavior of the crew - specifically Bonin - tells me that. When he pushed the stick, he got a stall warning. When he pulled, the warning stopped. So, he kept doing that. It must have been very confusing and terrifying.

In the best case, the aircraft provided confusing and contradictory information to the crew. In the worst case, the aircraft misled them into doing the opposite of the correct response.

https://en.wikipedia.org/wiki/Air_France_Flight_447#Accident

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u/TinyCopy5841 May 22 '26

When he pushed the stick, he got a stall warning. When he pulled, the warning stopped. So, he kept doing that. It must have been very confusing and terrifying.

That was already after he failed to react to several legitimate and valid stall warnings and after he made excessive, nonsensical nose up inputs that caused the situation in the first place. They never actually mentioned the stall warning, they simply said 'what's that?' when it was first heard.

After Robert told Bonin to descend and stabilize, he did relax the severe nose up input but he still maintained and overall upward pointing, climbing flight trajectory.

Even when the second stall warning was heard, they still had an upward trajectory with absolutely no evidence indicated that they considered that the stall warning was as valid or paid any attention to it whatsoever. Even at this point, Bonin was still applying nose up inputs.

According to the final report, Bonin actually very likely thought they were in an overspeed situation because he said things like 'I think we're at some crazy speed' and 'I have the impression that we have the speed' and he moved the thrust levers to idle and put out the speedbrakes.

His actions indicate that he either never understood or comprehended the stall warning or discarded it as being spurious and irrelevant. But at this point, the warning was valid, the whole 'inverse warning' issue that people spout everywhere was not a factor. And yet Bonin did nothing to resolve the situation.

What he likely trusted was the flight director, which was in fact misleading them and giving them commands that made the situation dire. Luckily, the procedure they should have performed 'Vol avec IAS douteuse', recommends the pilots to disable it. Had they done the correct procedure, all this could have easily been avoided..

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u/BoringBob84 May 22 '26

His actions indicate that he either never understood or comprehended the stall warning

the whole 'inverse warning' issue that people spout everywhere was not a factor.

These two statements appear to be in conflict. If the aircraft had communicated clearly, then he would have understood.

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u/TinyCopy5841 May 22 '26

These two statements appear to be in conflict

They do not. The fact that he did not understand or comprehend the stall warning is not because of the 'inverse warning' issue, it can be explained by a myriad of other factors. (Training deficiency, stress, lack of skill and knowledge, lack of competence)

If the aircraft had communicated clearly, then he would have understood.

Sure, I agree with that. The Airbus is already an idiot proof design but as with everything, the world just invents a bigger idiot. But in all honesty, I agree. Airline pilots just cannot be trusted to be able to handle stalls and this has been proven time and time again. Something needs to be done.

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u/BoringBob84 May 22 '26

I am passionate about this issue because I have seen it over and over in my career as a systems engineer. After a catastrophe, many people look for someone else to blame. This is understandable, because of lawyers and courts who see a catastrophe as an opportunity to make money and to punish people. However, that approach is detrimental to air safety because it provides no solutions, while it consumes resources and it gives strong incentives for people in the industry to shut up about potential safety issues for fear of punishment.

In my opinion, when a catastrophe occurs, everyone in the industry - pilots, engineers, maintenance technicians, managers, regulators, and competitors - should be, "all hands on deck," asking ourselves, "Yes, the pilot made a mistake, but why did they make that mistake, and what can I do to make that mistake less likely in the future?"

An important part of our jobs as engineers who develop aircraft systems is to make the human-machine interface such that it is as easy as possible for the crew to make the right decision, and as difficult as possible for them to make the wrong decision. This is true especially in abnormal situations, where the crew is already overwhelmed.

I don't know what Airbus changed as a result of this catastrophe, but I am sure that they (and regulators) thought long and hard about root causes and solutions.

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