Originally Posted by
Ian W
A little strong.
If your automatic stab trim is trimming down when you don't want it to. And even after you trim back up it starts trimming nose down again. and you repeat the sequence a couple more times... . even without a NNC checklist it would seem appropriate to switch the automated trim off. That is what the switches are for after all. Even if all you knew about the systems was a black box it is the aviator approach. The previous crew seemed to crack it - but the crash crew didn't - but they had gone through that sequence of auto trim down - manual electric trim up multiple times. So they knew what was happening and how it was counteracted. For some reason they didn't switch the auto stab trim off. I would really like to know where that flying spanner was, as this looks like a fault finding exercise gone wrong rather than set the systems safe and land.
Until we know whether the MCAS envelope is not anywhere near the normal day to day ops, there should be a caution about approaching that envelope in the NNC.