Deep stall hypothesis
Hello,
I'm not a professionnal pilot, but I have some basic understanding of physics and aerodynamics. I have multiple questions regarding AF 447:
First: how can the angle of attack can be that high (above 35 degrees)? Is there enough authority from the elevators or THS to maintain such a high angle?
Second: was this stall recoverable at all? If the AOA is that high, shouldn't the elevators be in the wake of the wing (and thus be useless)? Is this some kind of stable stall configuration?
Third: How could the captain maintain an almost zero roll (+- a few degrees) in such a stall? I have stalled before in gliders (I know this is not the same size weight altitude etc so it does not fully), and they tend to roll heavily on one side or another (it is very difficult to keep the wings level). I understand the BEA report on the 40 degrees roll oscillations when the stall started (which is for me consistent with a stall), but I don't understand why these large oscillations didn't persist
Fourth: why did the THS changed its position from +3 to +13 degrees at all? After all, wasn't the autotrim disconnected with the switch to alternate law? How can the computers give up because of lack of data, and still trim the plane (and using what information?)