How did lack of airspeed data cause AF-447 to enter an unrecoverable stall?
The most likely theory for the crash at this time seems to be that the aircraft entered a violent storm, the pitot tubes froze over, and the pilots stalled the aircraft b/c they didn't have reliable airspeed data. I don't really understand why a lack of airspeed data could lead to a stall. I fly hang gliders and have no indication of my airspeed, yet I can still keep it from stalling - because I know that if I shift the CG back to a certain point it will stall so I never exceed this position. Now, I'm sure the handling of an A-330 is very different from a hang glider, but why do you need reliable airspeed data to keep from stalling? To my understanding, a stall occurs when the AoA exceeds a critical value causing boundary layer separation on the top surface of the wing and loss of lift. And as far as I know, AoA is controlled solely by the trim of the horizontal stabilizer. And a sensible pilot or flight computer would not trim the aircraft past the critical AoA. I see how a powerful updraft or tail wind could cause the wing to stall before the attitude can adjust, but couldn't that happen regardless of whether you know your airspeed or not?