Originally Posted by
flyburg
Grebe, respectfully, but is that correct? From my FCOM
Control column actuated stabilizer trim cutout switches stop operation of the main
electric and autopilot trim when the control column movement opposes trim
direction. When the STAB TRIM override switch is positioned to OVERRIDE,
electric trim can be used regardless of control column position
It would appear to me that moving the CC in a direction opposite the trim(actuating the control column cut out switches) would stop ALL electric trim! Also the control column trim switches!
Often arriving in an airplane with electrice HYD pumps off with the control column slightly aft, trying to reset the trim to approx 5 units during preflight(as my college’s didn’t do so during taxi in), this is not possible with the control column trim switches until I push the control column slightly forward.
that is also the reason we have the STAB TRIM override switch I thought.
greetings.
This SLF will of course defer to a pilot.. But from my reading and understanding, you have described how an NG works and has worked for a few decades. Suggest you take a look at
https://www.satcom.guru/2019/10/flaw...-disaster.html
plus a half dozen other detailed of his detailed posts on the issue of MAX.
Also
https://leehamnews.com/2019/11/01/bj...-crash-part-1/ and now up to 6
https://leehamnews.com/2019/11/29/bj...-crash-part-5/
https://leehamnews.com/2019/12/06/bj...-crash-part-6/
And in simple terms ( as I undeerstand ) the MAX-MCAS system version 1.0 used on Lion and Ethopia had changed the description and function of the lower Console cutout switches such that both were in series, and either one cut all electric trim power and all autopilot power- thus were/are labeled PRI and B/U- and the ONLY method of moving stab was the (in)famous manual trim wheel.
And also sat guru wiring diagram on MAX shows MAX bypassed column/yoke ' mounted' cutout switch such that when yoke moved opposite to stab movement, nothing happened- eg stab movement was NOT stopped. Thus we have MCAS system acting like HAL .. .
