What you really mean might be that IAS and warnings of any kind at low speed might be involved here. Wind Shear comes to mind.
I think the twenty-one second interval to include ten seconds prior to a/p drop and eleven seconds after ("lost speeds", "alternate Law") contain the meat of the matter. If she was actually indicating 60 knots (less), what's the point in the post Stall discussion? The focus for me is on two handovers. One, the a/p to the PF flying (disregard his seat), and the degradation of Normal to Alternate (any one of them).
a/p loss: after the loss of autopilot, there were two Stall warnings. They cannot have been genuine, for the a/c commenced a climb without adding thrust, two things that would have caused a Stall post warning, if genuine,
they were not.
Stall warnings are genuine in ALaw, and these two were false, thus the a/c was not in ALaw after a/p drop. Having preceded airdata loss, the a/p deselected itself, which means the a/c remained in NLaw, with all prots as advertised.
In the short interval between "I have the controls" and rejection of two pairs of airdata, (eleven seconds), the PF knew he was in NLAW, and handled the a/c "Exactly as he was supposed to". Whatever the cause of Pitot sensing failure, it likely was not ICE, and it certainly was not precedent to a/p drop, since loss of reliable speeds and switch to ALaw was diagnosed (reported) after loss of autopilot.
Last edited by bearfoil; 8th Jun 2011 at 19:29.