AF 447 Thread No. 12

[DozyWannabe]

Originally Posted by Lonewolf_50

I may recall incorrectly, but weren't they already falling by the time Captain Dubois arrived in the cockpit?

You recall correctly. They were established in the stall and the descent by the time the CDB arrived.

I suspect _Phoenix_ may have meant to refer to the aircraft being in a nose-up attitude rather than "climbing". In fact at the point Dubois arrived, the status included these aspects:

1. Bonin had his sidestick at full NU and would continue to hold it there for a further half a minute approximately
2. The nose was up at the point he arrived, but was about to swing back down
3. Unfortunately, he arrived almost at the exact point that the excessive AoA began fouling the pitot tubes and messing up the ASI readings again

[EDIT : In fact, two seconds after Dubois arrives, the VSI is indicating a descent rate of -10,000ft/min. 13 seconds later, Bonin reports that he's lost VS indication - I have to wonder if it's possible that it was indicating, but that his mental model didn't expect to see the "needle" pegged near the bottom of the scale.]

Originally Posted by Winnerhofer

Schramm: Yes, the same well, uh, approach to stall means that one must never go beyond that. They were in unchartered waters.
Anchor: Well, yes because even Airbus had never envisaged such a situation.
Schramm: Indeed, in Normal Law, Airbus is unstallable.

The "anchor" is being disingenuous here. The Airbus FCOMs have always stated that it is possible to stall the aircraft outside of Normal Law. The AF representative (M. Schramm?) is, I suspect, doing a little bit of dancing around the point. In fact, "approach to stall" training and "stall recovery" are very different beasts - one thing that became apparent in the wake of this accident was that over the previous decade or so, the airlines as a whole started dropping stall recovery training from their recurrent syllabus in favour of stall avoidance ("approach to stall"). This was the case across almost every major airline and every type - from Airbus to Boeing and the remaining MDs.

This is why Boeing and Airbus subsequently collaborated on a programme to improve understanding of and training for stall scenarios.

FO Robert had the most time on type, this is true - and he certainly seems to have initially been the closest to understanding what was happening, but the likelihood is that the last time either he or Bonin actually trained for/performed a stall recovery in a powered aircraft was during their PPL training.