Originally Posted by
WillFlyForCheese
That is a very clear explanation - the most clear of anything I've read. Well done FCeng84.
What is interesting, then, is that MCAS activates without column input. If the purpose of MCAS is to essentially negate the lift of the engine cowling - which causes lift when AOA increases - then one would think the system would only activate as a result of column pull. In other words - the system is to create a consistent feel on the column - so why have it activate absent deliberate pull on the column? Why doesn't the system require both an increase in AOA and a pull on the column before it trims AND?
I'm glad to be able to provide some clarity. MCAS operates as a function of AOA with no regard to column position. As you state, "MCAS is to essentially negate lift (more specifically pitching moment) of the engine cowling". By cancelling out the nose up pitching moment from the cowling with increased AOA, MCAS smooths out the overall Cm-alpha (pitching moment vs. AOA) characteristic of the airplane so that column required to command a maneuver to high AOA does not decrease along the way.