Re:Boeing CEO ousted as 737 Max crisis deepens
by Gibbon1 on Tuesday December 24, 2019 @05:21PM
(#21875340)
> Exactly, the trim switches override the MCAS. That's why you use the trim switches to set it back to normal, then hit the cutoff switches.
On the 737 Max there is no way to disable the MCAS without also disabling the electric trim.
Re:Boeing CEO ousted as 737 Max crisis deepens
by WalterBright on Tuesday December 24, 2019 @05:32PM
(#21875390)
Sigh. With the electric trim enabled, the trim switches will override any MCAS commands. This is why, again:
1. trim to normal with the electric trim switches
2. cut off the stabilizer trim
Do it in that order. Doing step 2 before step 1 won't work.
Trying to argue that the trim system erratically coming on and driving the nose down is not "runaway trim" is arguing semantics. Runaway trim is when the trim is doing something dangerous without command from the pilot.
If the cockpit voice recorder reveals them discussing the definition of "runaway trim" and deciding that the instructions Boeing provided didn't apply, I'd be surprised and interested.
> MCAS also stops after the trim switches are hit.
Exactly, the trim switches override the MCAS. That's why you use the trim switches to set it back to normal, then hit the cutoff switches. That's what the Emergency Airworthiness Directive says to do.
> Reread the report.
I haven't read that anywhere. I don't know what report that is. Reference, please.