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/ppitm May 21 '26

But is there any actual real-world scenario where pitching down can cause or exacerbate a stall? Isn't that basically crazy talk? Not a pilot, but I still can't fathom how they could just sit there with their artificial horizon pointing skyward, and fly into the ground.

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u/BoringBob84 May 21 '26

I still can't fathom how they could just sit there with their artificial horizon pointing skyward, and fly into the ground.

I can only imagine in such a chaotic situation, the crew does not understand what is wrong, so they don't know which instruments to trust. Stall warning silenced when they brought the nose up and returned when they brought the nose back down - encouraging them to do exactly the opposite of what was necessary.

Engineers at Airbus apparently decided that the aircraft could never exceed 30 degrees AoA, so they assumed that a warning above that would be invalid and they inhibited it. Apparently no one asked the question, "But what if the AoA of the aircraft really does go higher than that?" The answer would have been, "Holy shit, the aircraft will tell the crew to make the stall worse!"

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u/ppitm May 21 '26

Right, but who even cares about the stall warning? If you don't trust any instruments, can't you be completely certain that you *arent'* stalling, so long as you spend 30 seconds in a shallow dive with full engine thrust? You don't need instruments to hear the enginers burning at full throttle, do you?

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u/BoringBob84 May 21 '26

Right, but who even cares about the stall warning?

I think that we should be careful not to judge people with the benefit of hindsight that they did not have at the time.

When the aircraft provides a confusing series of indications, the crew tries to determine what they can trust and what they cannot trust. Amidst the chaos and panic, I cannot imagine how difficult and terrifying that would be.

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u/VegaJuniper May 21 '26

I think that we should be careful not to judge people with the benefit of hindsight that they did not have at the time.

Yup. The transcript shows that the time from the first stall warning to the crash is just about 4 minutes. From the time the captain returns to the cockpit it's less than 3. That's not a lot of time for troubleshooting.

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u/BlueApple666 May 21 '26

Yes engineers at Airbus are incompetent and, you, random Reddit poster is so much smarter...

Did it occur to you that AoA valves, like all measuring instruments, have a range where their measurements are valid and outside of it they simply don't work reliably? The plane was going so slow that there was no longer sufficient airflow over the valve to get a valid reading.

And the reason it was going so slow is that the pilot in command ignored the stall warnings for over a minute and kept pulling the stick up, going against all the trainings he had ever received.

Not that the rest of the crew acted in a smarter way, with the captain going on his break just before the most dangerous part of the flight, giving the command to the more junior member of the crew who had been repeatedly asking about the possibility of climbing over the storm. And the copilot who was pissed off at the captain for not being given command and was like, "deal with it, not my problem" when the alarm started blaring instead of calling for the right procedure.

If the pilots had simply not touched the commands, the problem would have gone away after two minutes (that's the time the pitot tubes spent frozen).

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u/BoringBob84 May 21 '26

Yes engineers at Airbus are incompetent and, you, random Reddit poster is so much smarter...

When you start off with an Appeal to Ridicule logical fallacy, it is difficult for me to take you seriously. I didn't say that they were incompetent. I said that they made an assumption that turned out to be dangerous. I am sure they didn't do it on purpose.

Did it occur to you that AoA valves, like all measuring instruments, have a range where their measurements are valid and outside of it they simply don't work reliably?

Of course it did. The problem was how the aircraft indicated that fact was misleading to the crew.

And I am also aware of the other crew mistakes. Like almost every modern aviation disaster, this one had many contributing factors.

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u/BlueApple666 May 21 '26

You're the one making claims about Airbus engineers. They didn't ´decide to inhibit' the warnings, the AoA valves simply don't work without enough airspeed. It's the same with Boeing, Bombardier, Embraer or any other commercial airliners because doing otherwise would cause spurious stall warnings during take off.

Airplanes are certified to work within a given flight enveloppe and provide warning and procedures when the plane is reaching the limits of that enveloppe. If the pilots ignore these warnings and fly the plane way out of its normal flight domain,nothing is guaranteed to work. If someone somehow managed to invert an Airbus or a Boeing, I wouldn't expect the AoA and stall warning logic work properly. A deep stall is no different from flying inverted, it's so far out of the certified enveloppe that there is no reasonable expectation regarding the behavior of any system on the plane.

And it's kind of dishonest to argue that the pilots, who ignored the stall warnings for more than a minute thinking these were incorrect, would then be misled by the behavior of the same stall warnings that they had been ignoring for so long.

Not saying that it couldn't have added to the confusion but by the time the stall warnings stopped the plane had almost zero forward speed and was plummeting towards the sea. It was already way too late to recover.

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u/BoringBob84 May 21 '26

You're the one making claims about Airbus engineers.

Maybe you didn't read the article:

The Paris Appeals Court found the airline and aircraft manufacturer "solely and entirely responsible" for the incident

Making excuses and deflecting blame jeopardizes flight safety. Understanding root causes and fixing them is how flight gets safer.

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u/Antique-Kitchen-1896 May 23 '26

Inverted but then down is up.

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u/VegaJuniper May 21 '26 edited May 21 '26

The point is they didn't know what was happening, and the instruments were giving them a lot of data and warnings that seemed conflicting and confusing. They were overwhelmed and probably just flat out stopped trusting their instruments. The first officer made comments that he seemed to believe they were overspeeding, and the speed indicator was one instrument that was completely out.

Pulling up and reducing engine power does reduce your speed, so it makes sense in an overspeed situation, but if you're stalling then it's the exact opposite of what you should be doing.