[exidy]

The behaviour you describe above only occurred after the pilot flying stalled the plane. There was a procedure for unreliable airspeed indication. Had the pilot flying performed it, the situation would have been resolved without incident.

AF could perhaps be held liable for insufficient training on high-altitude stalls or recognising and responding to reversions to alternate law. But it's hard to see how Airbus can be responsible for a pilot ignoring the most basic first response.

[fweimer]

The article from this subthread contradicts this, though. Regarding recoverability of the situation, it says this:

> By now the airspeed indications had returned to normal, but the pilots had already set in motion a sequence of events which could not be undone.

That was before the prolonged stall warnings. But maybe this phrasing is just an embellishment?

But further down, the article is pretty clear that the training was inadequate for this type of unreliable airspeed indication:

> Although procedures for other phases of flight could be found in the manual, the training conditioned pilots to expect unreliable airspeed events during climb, to which they would respond with a steady nose-up pitch and high power setting that would ensure a shallow ascent. Such a response would be completely inappropriate in cruise.

[exidy]

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.

[fweimer]

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.

[exidy]

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