Originally Posted by
alf5071h
jimtx, you mistakenly associate the successful outcome as an indication that the crew took the correct action, i.e. that they understood the situation.
It is just as likely, or more so, that they formed ‘a strong but wrong’ belief that the AoA and IAS alerts - the airdata was interfering with STS, so trim was disabled. This was after they had followed the drills for UAS, and ALT Disagree. See report p 21.
The accident crew could similarly have concentrated on the air-data problems and were managing the conflicting stick-shake and low speed awareness, with the different airspeed indications - as did the previous crew.
However, thereafter with flap retraction and trim problems, the latter crew held an equally ‘strong but wrong’ belief that UAS was the dominant issue. Again refer to the report re ATC and speed / height checks p 23.
Outcome knowledge does not reflect the quality of the decision - hindsight bias.
I’m sure they did not understand the situation. But Boeing says what they did is the correct procedure for a MCAS malfunction. What they didn’t know and what Boeing hasn’t said is whether dissabling MCAS put them at risk for what MCAS protects against. I’m guessing not but suppose in a turn they overbanked slightly and pulled and that was in the envelope where the MCAS should have functioned. Is MCAS that important if Boeing uses the runaway trim procedure and adds no caution about the loss of MCAS?