asc12: a thought on stall and directional control, if we go forwrad on the assumption that at some point aircraft was stalled.
When stalled in turbulent air, is there not the risk of asymmetric lift on the wings inducing a rolling moment? Once such a roll is begun, how does one stop it until the control surfaces are once again effective? (On some aircraft, maybe rudder opposite direction of roll, but that's type dependent, and may be limited to small/light aircraft).
This leads me to the attitude gyros (which feed the PFD) used in the A330: if your aircraft is not designed as an aerobatic machine, would you install a 3D gyro?
I ask because I flew a trainer that we used for VFR spin training and VFR aerobatics training. The attitude gyro typically tumbled, during spins and aerobatic flight, unlike the gyros in high performance jets that allowed "on instrument scan" aerobatic maneuvers (like a barrel roll) with no degradation to the gyro's ability to provide reliable attitude reference.
I have no idea how much 3-axis disturbance it would take to cause such havoc in the A330's attitude reference system, but if such disturbance occurred, that's one more difficult flying task to undertake, recovering from a 3 axis upset using a partial panel scan, that even when one is prepared can be difficult.
I don't envy the BEA and the various search parties their search problem before much was found, since establishing datum rested on assumption, rather than facts, regarding track over ground.