Originally Posted by
Peter H
If you don't use trim to solve a feel requirement, them MCAS triggered trim runaway is impossible.
PPS If you want to argue that the MAX need high-reliability computers to run any software handling of the stab, surely this argument
also applies to other variants of the 737.
I you remove the code for MCAS then it can't generate a runaway
But the Flight Control System have been connected to the trim for decades, and a bit-flip in other functions of the Flight Control Computers might be able to generate a 'continues' runaway. (Way easier to diagnose quickly, than a intermittent runaway)
I see MCAS as a change that changed the reliability of the FCS from being several magnitudes better than specified by DAL C, to about the limit of DAL C.
You can't complain when a DAL C design, changes from e.g. DAL B to DAL C reliability following a design change. (The same could have happened due to e.g. a die shrink )
Using one AoA sensor might sufficient for DAL C, but not for the required DAL A.