Originally Posted by CONF iture
Your graceful degraduation is not wanted - keep things simple.
Not my airplane, but the following represents my thoughts on how the AF447 crew got so far out of sync with the aircraft.
Normal Law-makes sense
Alt 1 Law-graceful degradation, but the risk is that a heavily stressed pilot may not recognize his reduced protections. (NA to AF447.)
Alt 2 Law-graceful degradation-NOT.
It is an awkward stepchild. It is fairly clear from the narrative that Bonin never integrated the loss of protections into his flying. It would have been better if the aircraft had dropped into full Direct law. It is likely then that the stick response would have been sufficiently different that failure to recognize Direct law would be impossible. Direct law has the added benefit of the HS trim staying put at last setting unless changed by the crew.
It is fairly clear to me that the Crew of AF447 lost confidence in the flight control system's proper operation, and that doubt kept them from recognizing that they were stalled. The doubt began with the initial roll oscillation and escalated as the aircraft stalled. Flying in a unfamiliar part of the envelope was a contributing factor. (ALT2 at altitude)
When you put a guy in an unfamiliar situation, you are flipping coins as to how he will respond. Every so often you will come up tails. (i.e. the wrong answer).