QuagmireAirlines
Quote:
Originally Posted by
ecto1 
MCAS (a proper one) would need to be active at any pitch angle and vertical speed. One can pull to a stall while going up, level or down..
OK, that is reasonable.
How about this envelope protection cut-out: Turn off MCAS when airspeed is greater than 200 knots.
That is simple, and uses different sensor sources (pressure sensors on the nose) to disable MCAS which works off AoA vanes.
Ultimately the decision by Boeing to simply turn off MCAS when the dual AoA vanes disagree may be the best approach.
If it was me, I'd disable MCAS for those high (>200 knots should do it) airspeeds, and also compare the two AoA vanes to computed Inertial Alpha (pitch-gamma) as a sanity check to find the bad AoA vane when AoA disagrees happen.
MCAS is
not a stall protection system. It is there to meet the requirements of 14 CFR 25.173 that the pull force on the control column should be linear with speed and AoA. With the Max the pull force gets lighter as the AoA gets close to stall but it is not a stall prevention device. Apparently, Boeing was more concerned about handling problems at high AoA in steep turns somewhere most pilots would not take a 73.