Originally Posted by
threemiles
No. I take an aviation document as literal and binding. What you say may be from some private working papers, which is not an official numbered published document. So can be anything, including fake.
???
I’m explaining how the 737 stab trim works, from the manuals. Not some ‘private working papers”. I know it works that way because I’ve been flying the thing most of my life.
I even know it works that way because I’ve used it that way on the ground. Actual aircraft, not Sim. You can use yoke trim to just forward of 4 units, then it stops. You can wind it forward to 0 units manually, then you can use yoke trim to electrically wind it back. That’s how it was designed, and that’s how it performs.
EASA brought it up because it was at odds with some certification criteria, and then allowed it because it made sense from a safety perspective.
Now whether it works at 365 knots with sufficient aft control column for level flight is an entirely different question. That question is currently under congecture. My point is that the EASA document is irrelevant to that congecture because that was not the subject of the EASA document, and the word “authority” is being mis-interpreted by some here. I doubt it was mis-interpreted by the actual audience it was intended for.
We know it works at 325-330 knots, because it did. It’s on the FDR trace. Yoke trim from 0.4-2.3 units.
I hope
that helps.