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A comment on FAA faces dilemma over 737 Max wiring flaw that Boeing missed. Parent comment

Re:FAA faces dilemma over 737 Max wiring flaw that Boeing mi... by Gwypaas on Sunday February 16, 2020 @05:44PM (#22344200)
Today it's mitigated by the pilot. Runaway Stabilizer is a memory-item. [1]

This is the same memory item Boeing thought would mitigate MCAS, since that is essentially a runaway stabilizer trim, although in retrospect behaving in a very different manner making it much harder to diagnose.

[1]: http://www.b737.org.uk/runawaystab.htm

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Re:FAA faces dilemma over 737 Max wiring flaw that Boeing mi... by kds3 on Sunday February 16, 2020 @05:59PM (#22344269)
Runaway Stabilizer / MCAS cases can be mitigated by the pilots (they can use cutoff switches and do manual trim), but not this kind of electrical short:

> Furthermore, the electrical power in that wire could circumvent the cutoff switches in the cockpit that, in the event of such a stabilizer runaway, are used to kill electrical power to the tail. Theoretically, the pilots could be unable to shut it off.

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Re:FAA faces dilemma over 737 Max wiring flaw that Boeing mi... by mlyle on Sunday February 16, 2020 @06:15PM (#22344323)
It's not a great mitigation, but the last thing on runaway stabilizer's memory list is to "grasp and firmly hold" the stab trim wheel.
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Re:FAA faces dilemma over 737 Max wiring flaw that Boeing mi... by SAI_Peregrinus on Sunday February 16, 2020 @06:44PM (#22344457)
The electric motors can apply more power than a human can resist. So that's not exactly helpful.
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Re:FAA faces dilemma over 737 Max wiring flaw that Boeing mi... by mlyle on Monday February 17, 2020 @12:45PM (#22349214)
The system is engineered so that an operator holding the trim wheel wins, via a clutch mechanism.
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Re:FAA faces dilemma over 737 Max wiring flaw that Boeing mi... by userbinator on Sunday February 16, 2020 @07:43PM (#22344697)
I believe there is a clutch mechanism. There are videos on YouTube of pilots doing this (in a simulator.)
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