Originally Posted by
jimtx
Yet the certification authority and the manufacturer don't see any need to warn you about avoiding the flight regimes that MCAS was added to protect when in fact you would be without it if you had to disable electric trim for a malfunction.
This is my big question too. Although in fact I can see that a system
could be needed to meet certification but not need to be explained to pilots because it isn't significant in effect or likelihood, as far as I can see the certification itself also requires such a system to be visible to pilots.
FAR 25.672 (a)
A warning [...] must be provided for any failure in the stability augmentation system
So where is it, what does it say? "I'm sorry Dave, something has failed, something you don't know about, it's not important really" ? Really?
Then there is 25.672(b), which says the pilot must be able to deactivate the system or override it with normal control movement. You can't deactivate something you don't know exists (except by accident by deactivating something else), and MCAS cannot be overridden by column position.
Looking at the NG speed trim description I can fit it to 25.672, despite it having a high-AOA trim-down function (which MCAS is probably the b*****d offspring off) - because that function is part of speed trim, there to enable speed trim function to work at high AOA, and therefore there is a fail-warning, and speed-trim can be overridden by the column (column cutouts). MCAS doesn't seem to fit, to me.