Boeing Company (BA)

[Porgie Tirebiter]

If you fly any airplane, you know you need to "haul back" on the yoke in a wind-up turn. If an airplane has positive pitch stability it will return to the trim airspeed should the pilot let go of the controls. Because of the thrust vector of the LEAP installation the airplane would tend toward a stick neutral feel. In other words, would tend to develop a stability in the deviation from trim airspeed and not return should the pilot let go of the controls. MCAS was intended to run in some nose down trim to counter the stick neutral tendency.

My own thought is that MCAS needs an input completely independent of the stall warning system (so that one failure doesn't cause two problems) and most importantly a feedback which reads stick force so MCAS will disengage at some sort of reasonable amount of force level. Just like autopilots already do.

And, by the way, Muilenberg is on record numerous times correcting the media regarding MCAS not being an anti stall system.

Again, while this article is not about the 737 itself, it does an excellent job of describing the problem MCAS was developed to solve: https://airfactsjournal.com/2013/05/the-weight-and-the-balance/