Originally Posted by
ManaAdaSystem
How large? I have tried to let it trim without counter trimming just to see how far out of trim the aircraft gets. I get more and more back pressure on the yoke but STS keeps trimming.
On top of that, STS trims on all departures, not only in the light aircraft, high thrust aft CG situation.
It’s a weird system that I could do without.
The switch involved is the same one that interrupts pilot electric pitch trim if opposite the column displacement direction. I believe this interrupt is also active on the ground. When positioning the stabilizer for takeoff using wheel mounted thumb switch try moving the column in the opposite direction at the same time to see how far it has to be out of detent before stabilizer motion stops even though thumb switch remains activated. A note of caution that thumb switch input in opposition to column such that the column cutout activates if held for very long may trip a monitor designed to detect persistent contradictory column and trim commands. That might take some explaining. I apologize that I don't know the details on such monitoring (in particular how long the condition must persist before said monitor trips). I'm sure there must be some 737 savvy PPRUNErs out there who know and by the amount of traffic on this thread they are probably monitoring.