Originally Posted by
tdracer
Why? The revised MCAS logic uses both AoA inputs (and IIRC, will be updated with a synthetic AoA calculation at some future point) and they didn't need change the basic architecture for the update.
Actually, my understanding is, MCAS-1 were 2 independent systems L/R, which did not communicate, but with only some kind of logic to switch-over on airplane boot-up. With MCAS-2, these systems now communicate with each-other to interact about (at least) the presumed health of the AoA input values. With one AoA input out of action, the AoA issue handling is returned to the pilot, according Boeing philosophy.
Regarding the synthetic AoA, this has been "agreed", though also tied to the MAX -10 (maybe also the -7) appearance. No -10 and the synthetic AoA might end up with a premature death. The FAA will be having weak knees, due to Congressional pressure, though It has to be seen, what EASA and China think about this. It was EASA, which was firmly after the 3rd AoA sensor, with the degrade compromise, it might be synthetic.