Originally Posted by
Smythe
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Seattle Times reporting that Boeing changed the function of the stab trim switches on the MAX vs NG. (does not appear to have told anyone)
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Yes on the first part (covered extensively in previous threads). No on the second part - the change in labeling and function was disclosed in the FCOM. The changes did not include a detailed wiring diagram, but one was not needed either.
Seattle Times article can be found here:
link
Also covered extensively in previous threads, the change in functionality made no difference procedurally. The 737NG and the MAX runaway stab procedure calls for the use of
both switches. I had speculated previously that the two switches were retained on the MAX, in part, to provide commonality with the NG. The article above has this statement from a Boeing spokesperson:
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Boeing said in a statement that the company had historically called for pilots to flip both switches to shut of a problematic or “runaway” stabilizer, so the change on the MAX ensured that the function of the switches matched that procedure. The company said the two switches “were retained for commonality of the crew interface.”
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So it appears that speculation was correct.