Originally Posted by
L39 Guy
The moment the aircraft lifted off in all of these situations they had an unreliable airspeed situation - disparity between airspeed indicators, the stick shaker active.
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This is a textbook UAS event. It's a memory drill - flight directors off, autopilot off, auto throttle off, set an appropriate pitch/power setting for phase of flight. None of this was done. And, as I pointed out earlier, even if the Ethiopean crew thought it was a bona fide stall, you do not engage the autopilot. Period. Moreover, if the aircraft is indeed in a stall, why on earth would one raise a high lift device like the flaps and deepen the stall? Airmanship again. So even before the MCAS event, things were way off the rails.
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Not sure that we know for a fact that ET had a UAS warning. The (frustratingly limited) log in the ET prelim report reports that the displayed speeds diverged but no mention of UAS.
From the FDR plot the 2 speeds are not widely different at first although it is hard to read absolute values.
What is the trigger for UAS warning?
Can the autopilot be engaged while UAS warn is active?
Also puzzled by 'the stick shaker active' in above, is this an expected side effect of all UAS events?
I could well be missing something here so stand ready to be corrected/further enlightened.