Originally Posted by
FGD135
No, the MCAS is absolutely not there for the stall scenario. It is to improve manual handling characteristics at flight near the stall. It is not for stall recovery. If Boeing had wanted that, they would have installed a “stick pusher”, which is a simple system, common to many airliners.
No, it is not trying to pull the nose down. It is trying to change how the plane feels when manually flown at speeds near the stall.
It can pull the nose down, as we now know, but that was never Boeing’s intention.
MCAS is qualified in many sources as fundamentally a stall prevention system.
The original Boeing document provided to the FAA included a description specifying a limit to how much the system could move the horizontal tail — a limit of 0.6 degrees (turned out to be actually 2.5 deg), out of a physical maximum of just less than 5 degrees of nose-down movement (20+deg with the new 2.5 deg rotation (don't forget to add it can reset indefinitely)). From this statement, it's pretty clear that the intention was to pull the nose down hence the wording, "5 degrees of nose-down movement".
Since MCAS changes the position of the horizontal stab it is absolutely effecting the pitch attitude of the plane. Or if you rather, it is effecting the pitch down forces on the plane.