Originally Posted by
OldnGrounded
This, to me, a once-upon-a time mech and long-time engineer, is the "truthiest" post of this long thread. From the moment, in the Lion Air thread that we began to understand the existence and potential reality of MCAS, my image of being on the flight deck of one of these accident aircraft has been eerily like Aloha_KSA's depiction.
I understand why some pilots want to believe that they would have recognized what was happening, hit the pedestal cutout switches and trimmed the aircraft manually, but everything I know about human factors in sudden and new emergency situations says, "No, you very probably would not." This whole, frankly unforgivable, design and certification mess is a formula that was destined to end up with HAL killing everyone.
The problem with the above is that at least in the Lion Air accident it did not happen that way. The MCAS commanded 2.5 units of nosedown trim which was countered by the CA retrimming the aircraft. 5 seconds later MCAS again commanded 2.5 units nose down trim and again it was electrically countered by the Captain. This cycle repeated itself 21 times. That’s a lot of time to diagnose the problem. MCAS does not drive the stab full nose down and cause a instant plunge into the ground. It moves in 2.5 degree increments and electrical trim is available to counter it. Not that difficult to retrim electrically and then disable the trim motors. Your now in trim and have manual trim available.