Originally Posted by
FGD135
It seems that everybody here wants to bash Boeing for not training pilots at how to deal with the MCAS inadvertent activation. But Boeing have provided training and guidance. The problem is that this guidance wasn't followed by the Lion Air crew - and possibly the Ethiopian crew.
The guidance from Boeing would have related to uncommanded/inappropriate trim activation. I'm not a 737 pilot, and I don't have a 737 checklist handy, but it absolutely certainly would have had a documented procedure for this scenario which would have called for the deactivation, via the stab cutout switches, of the electric stab trim.
The issue isn’t (just) whether Boeing provided guidance. It is whether it is reasonable to expect the pilots to recognize the situation in order to follow that guidance.
Sitting dumb fat and happy with everything going well and suddenly the trim starts moving, sure easy enough to recognize and action. Throw in AoA disagree, unreliable airspeed, stick shaker, etc. then maybe that becomes a more difficult problem. It looks like in both the Lionair accident and the preceding flight, neither crew thought about trim cutout initially. Eventually the preceding flight crew did, and did cut it out, but it took several minutes.
This is where it looks like a poor FMEA analysis was done, treating the need for MCAS cutout as a single fault situation. It seems that a single sensor fault in the AOA can effectively lead to a double fault, and reliable airspeed, and inappropriate MCAS activation. Well rather a single fault causing two significant system failures, getting the pilots a definite challenge.