Originally Posted by
threemiles
This certification statement about the authority of the trim wheel over the entire flight envelope is certainly not correct, if the trim wheel cannot be cranked ANU at 10000 ft, 320 KIAS.
The holes line up in the cheese: Boeing, crew, FAA, EASA, ...
Your point about the certification statement is well made and whoever made such a statement to a regulator must be feeling hot under the collar. Boeing seemed to accept that electric trim on the Max did not work over the entire flight envelope and somehow claimed this as a safety feature. To go on to claim that the trim wheels cover the entire envelope, when the previous wisdom was that it did not, starts to smell less like a mistake and more like deliberate subterfuge to try and cover-up a certification breach.
As I stated earlier, nobody is sure of the actual envelope where electric trim and manual trim are assured, including on the 737NGs that are operating today. If I was representing an AOC holder I would be seeking urgent clarification of the trimmable flight envelope for the current 737 family.