Originally Posted by
Henry III
The points I found most salient were:
- When an airplane's air speed indicator fails (for whatever reason), there is a 'universal' procedure to allow continued safe flight: engines at 85% thrust and pitch set to nose 5° up.
- When the A330 is in autopilot (or auto-thust) mode, the throttle (thrust lever) does not move in reflection of changes made to actual thrust - and this is unlike most other aircraft.
- Having entered turbulence, the thrust would have been (automatically) lowered to about 70-75% (to reduce stress).
- When the autopilot disengaged, the flight crew may not have realized that the thrust was too low, as the throttle position could still have been suggesting the pre-turbulence level (> 85%).
- The pilot would certainly have known to set the pitch to +5° but, with the thrust being too low, this would almost certainly have caused a (quite sudden) stall. Further, if this stall occurred in one wing (even very slightly) before the other, then the aircraft would enter a catastrophic sideways/downward lunge, which even very experienced commercial pilots are not really trained to handle.
-- Henry
I agree it was better than most documentaries on crashes and you have covered the main salient points. There were a couple things I thought stretching it a bit though. When they talked about the throttles not moving, the way it was spoken about was it was a design flaw, as was the case with the screen of power dials being in the middle of the cockpit. The issue I had with that implication was that phrase 'most other aircraft' - if all FBW airbuses operate these ways and these are airbus pilots then the implication was really unnecessary. After all, trained airbus pilots would surely know this, no and is SOP. THe stress of the situation will cause mistakes, not the cockpit layout surely. Second, the idea that commercial pilots should undertake training to get out of a stall is interesting but surely impractical as getting an F16 out of trouble and an airbus are rather different propositions.
IT seems that the catastrophic chain of events brought this machine down, any one of which not happening would have ended the danger.