Originally Posted by robertbartsch
So the nose-up input was likely caused by the incorrect assumption that AS was too high; right?
a) If incorect airspeed was displayed on RHS (not recorded), it would be droping like the two other sources. Hence, why this assumption?
b) First emergency signal was a "stall warning"... not overspeed.
c) PF initial reaction was contrary to a) & b)... unless those signals were duely ignored because of an unknown factor, or that he thought to be the right thing to do in response to a) and b)... and this could have been in case of CFIT alert in Normal law (except thrust settings, but TOGA should kick automatically by alpha_floor function). What make me think it could be an explanation is that it is also exactly what the PF did after the stall warning at 0210:51 (he manually applied TOGA and pitched up).
Originally Posted by robertbartsch
If a stall was being caused by too much AS, wouldn't there be other physical indications (wing shutter, nose over, etc.) to confirm this?
High speed buffet would take an increase of airspeed above (real) Mach 0.88-0.89 and they were still flying at 0.80. There is no mention of any particular turbulence severity that could have caused a real overshooting of MMO. On the other hand, switching to ALTERNATE would also reduce the MMO limit displayed on PFD down to Mach 0.82 (putting the limit much closer to their real airspeed)... hence, what if the pilot saw that gauge high limit moving close to its airspeed, if it was actually rightly displayed? Could he interpret the warning being an "overspeed" instead of "stall" (even if voiced)?.