PJ2,
Quote:
The idea isn't to shut down a path of thought but to test a line of thought against serious objections. That is the way investigations are done.
Agreed. I think that it is equally incumbent on those who disagree with a clearly-stated point – and who have competence and experience in that area – to provide a specific counter-argument.
Quote, re the period prior to 0210z:
I think things began to develop before the loss of airspeed...
Yes. Things were developing, and are probably the key to the events that followed. But, if you refer to the first discrepancy in the flight regime, I don't think we can assume that it was necessarily a loss of airspeed.
If we stick to the theory of progressively freezing pitot-probes, it is unclear whether they result in an over-reading of airspeed, or the reverse. The BEA analysis of previous events shows a large proportion of cases where a stall warning occurred. In every case, there had already been a reversion to Alternate Law. As I understand it, the stall warning in Alternate Law is based on indicated airspeed falling to a certain threshold, not the AoA. As the indications are unreliable, the stall warning might have occurred despite the airspeed being normal, or even above normal.
To be simplistic: if a pitot tube is blocked, but the static is clear, that is very likely to result in an under-reading of airspeed. (We've visited this one before...)
Regards,
Chris
Last edited by Chris Scott; 22nd Apr 2011 at 09:44.