Originally Posted by
RickNRoll
It changes the feel by changing the pitch of the whole plane. Which is a weird way to change the feel of the control column. Change the attitude of the whole plane.
Not really; recall that the system is functional only in manual flight, which is when the pilot is in the control loop. The pilots task is to fly the aircraft to an attitude that gives the performance that is desired. With normal, compliant control characteristics, static stability results in an aircraft that wants to revert to trim speed (AOA) and so if below the trim speed, it will want to pitch down, which is countered by a pull force from the pilot to obtain an off trim speed condition that the pilot desires. That is exactly the same situation that occurs with MCAS, ll it is doing is exacerbating the off trim speed margin so that the desired force profile is achieved. With the information on the area of 203(a) that also indicates that the tendency for a reduction in stick force approaching an accelerated stall is offset by the nose down trim. If the pilot wants to fly at that AOA, he can, the force will be appropriate for a naturally compliant system. Arguably it is also similar in outcome to a stick pusher, except that it has input to the trim over time, not a direct and prompt push on the elevator. Stick pushers are pretty savage in their response compared to the initial triggering response of MCAS.