To those saying "use the runaway stab procedure", and claiming that it clearly says to put the plane back in trim with the MET (which, as a programmer, I don't read from the posted checklist at all, but I digress), how would that work if the runaway is not caused by MCAS, but rather an actual, possibly intermittent, electrical fault in the trim motor?
"Oh, it's trimming down? Weird. Might be STS. Wait, it's going pretty far down. Might be MCAS. Oh, it's stopped. But this is a bit too far down, let me trim back. Hmm, the pickle switches work, I'm trimming back up. Seems OK now. Wait, it's trimming down again, a lot. It's got to be MCAS. Stupid thing, didn't they fix the software? Hm, it's not responding to the pickle switch now. I thought MCAS stopped when I try to trim up? Am I remembering right? Might be a glitch? MCAS will only run for 10 seconds anyway. Once it stops, I'll trim up. Obviously I don't wanna throw the cutouts while I'm trimmed so far down. I know how that ends. Okay, MCAS should definitely be stopping now. It's... not stopping? Oh ****. This is something else! Okay, stab tirm cutout! Oh hell, this is way nose down now. Try the manual trim wheel. Nope, it won't budge. Well, crap. What do I do now?"
My point is that trying to trim back to normal with MET in a suspected runaway trim scenario is a gamble. If it's MCAS, you win. But if it's not, then while you're fumbling with the pickle switches trying to see how the trim responds, the trim could be running further and further away, leaving you even worse off than if you had hit the cutouts earlier. How much time do you allow for this "troubleshooting"? How large of a decision tree are you expecting "average" pilots to be able to recall in this situation, especially if they've got other alarms going on?
Last edited by Tobin; 6th Oct 2019 at 04:16.