Originally Posted by Mr Optimistic
OK but eventually the AoA went well over and the aircraft stalled. It is inconceivable that somehow the fwd speed got to 60knots unstalled, so at some stage it should have been continuous until the fwd speed did indeed reach 60kts. One can only surmise that knowledge of previous false stall warnings in UAS conditions were somewhere present in their minds but if the plane was flown upto and into a stall wouldn't the warning have been somewhat insistent ?
About 40 seconds later at 2:10:51 the stall warning was triggered again. The airplane probably stalled between 5 - 10 seconds after that, just before reaching its apogee of FL380 at 2:11:06. The airspeed probably remained above 120 kCAS during the descent. The low indicated speeds of 60, then 30 kt were caused by pressure disturbances at extreme AoA - the pitot pressure being lower than the free-stream total pressure and the pressure at the static source being higher than the ambient pressure.