> MCAS was devised to fulfill an airworthiness certification condition in 14 CFR 25.173 and 14 CFR 25.175. In high angle-of-attack (AoA) flight configuration, it is required that stick force/g (the stick force necessary to produce (hold) an incremental normal acceleration of 1g) and stick movement/g (ditto mutatis mutandis) must increase (or at least not decrease) with an increase in AoA (thanks to Clive Leyman for this formulation). I understand that in flight test, in which “wind-up turns” were conducted (a turn with increasing angle of bank; an increasing angle of bank means ceteris paribus increasing AoA), this condition was not fulfilled.
-- https://abnormaldistribution.org/index.php/2019/04/30/ieee-s...
And also to stop the plane dropping out of the sky!
@HPsquared “.. The plane is perfectly stable without MCAS ..”
NO, no, no it isn't .. doesn't matter how many different ways you re-arrange the word salad. MCAS is a software kludge to compensate for an unstable airframe