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Comment by exidy | Hacker News Reader

Once the aircraft was stalled there was a narrow window to recover from it, which obviously did not occur. But the stall was entirely caused by pilot input of full nose up! The procedure for unreliable airspeed (which was in both the QRH and the FCOM) was simply to fly a known safe power / pitch from the tables provided in the QRH.

At no time was any of the pilot's Attitude Indicators (Artificial Horizons) inoperative -- all they had to do was maintain straight and level flight at a known power setting and everyone would have come home safely.

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I see. I assumed that given they were flying at 37,000ft, they would have more time to react. But the BEA report says that after autopilot disconnection, only two minutes passed until they reached this situation:

> Only an extremely purposeful crew with a good comprehension of the situation could have carried out a manoeuvre that would have made it possible to perhaps recover control of the aeroplane. In fact, the crew had almost completely lost control of the situation.

I had no idea that things could go wrong so quickly, even at that altitude.

You are absolutely correct that things can go wrong very quickly, especially at altitude. Modern planes fly very high for reasons of efficiency, but as the air thins, the window between stall speed and overspeed becomes narrower[0]. That's why piloting always emphasises the need to be thinking ahead of what the plane is doing and not following it.

For this incident, they were flying at FL350 (35,000 feet) and had a service ceiling of FL370 at their current weight -- that's a difference of only 2,000 feet. Within 30 seconds of the autopilot disconnecting, Bonin put the aircraft into a 7,000 feet/minute climb! So that margin was eaten up very very quickly.

If you're interested in aircraft incidents and accidents I recommend Petter Hörnfeldt's excellent YouTube channel Mentour Pilot[1]. He goes into deep technical detail and has covered not just AF447 but many other incidents where the pilot lost situational awareness and put a perfectly working plane into the ground.

[0] https://www.boldmethod.com/learn-to-fly/aerodynamics/coffin-...

[1] https://www.youtube.com/@MentourPilot

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