Originally Posted by oldengmkr
The A340 scenario, with a zoom climb resulting in decreased forward velocity followed by a deep stall, with perhaps even a tail down fall to the water, fits the roughly known envelope of AF 447. There does not seem to have been any aspects of this irrefutably rejected by the responses and counter comments provided to date in this thread - or did I miss something?
I have previously argued that the A340 airprox incident does not fit the AF447 scenario because triggering alpha-prot law disengages the autopilot and, in the case of AF447, that was immediately followed by reversion to ALT law. Since the High Angle of Attack protection is not available in ALT law, I assumed that the reversion would cancel alpha-prot if it had been activated prior to that point. Maybe we need to review that assumption?
EDIT:: If alpha-prot had been activated prior to reversion to ALT law, and continued to be active after that point, it would maintain AoA at alpha-prot, i.e. it would not lead to deep stall. On the other hand, it may have handed the pilots an aircraft at relatively high AoA, low speed and possibly unusual pitch attitude.
PS:: Think of QF32, where the protection 'recovered' the airplane to an AoA (minus 5 deg) that was well below the threshold it was intended to protect.
Regards,
HN39