Originally Posted by
gums
Salute FC !
Yeah, AoA seems to be the driver for the pulses, and mach is a function that fades out the MCAS what? a) duration of pulse, b) rate of stab movement, c) amount of stab movement ( which necessarily appears a function of "a" and "b") or all of the above?
The available literature says the mach will limit MCAS cmds according to "some" function/equation until what? 0.68 M ? And then no more MCAS above that, if I read it correctly.
So AoA must not be as big of a factor at higher altitudes and normal cruise mach, huh?
Point being that "q" must be important, and Machinbird's question about linearity of the plane's static stability coefficients when near certain AoA and "q" values must be a player for certification.
Oh well, all very technical, but knowing what the plane is supposed to do and what the "help" provided by Hal is supposed to do is a good thing.
Gums asks...
The amount of airplane nose down stabilizer that MCAS commands is a function of both Mach number and the amount that AOA has exceeded the MCAS activation threshold (itself a function of speed/Mach). When MCAS commands the stab, it always moves at the MCAS rate of 0.27 deg/sec. The duration of the MCAS stab command is how ever long it takes to move the stabilizer at the MCAS rate the amount of incremental stabilizer commanded by MCAS.