Originally Posted by
alf5071h
DaveReidUK, #3647, Icarus2001, quentinc
“… no evidence that it's the case for electric trim.”
Indications in the EASA reference ‘Equivalent Safety Case’ suggest otherwise.
“Simulation has demonstrated that the thumb switch trim does not have enough authority to completely trim the aircraft longitudinally in certain corners of the flight envelope, e.g. gear up/flaps up, aft center of gravity, near Vmo/Mmo corner, and gear down/flaps up, at speeds above 230 kts.”
This has already been discussed, the EASA document refers to the designed limits for electric trim, that do not allow you to trim electrically outside its designed range, even though the range available with mechanical trim is larger, and in some situations you need to access a larger range than manual electric trim allows. Those design limits don't apply when you trim electrically ANU to counter MCAS. They would only apply if you would try to trim further AND electrically, after you reached the AND design limit for manual electric trim (lower than 3.95 units on the 737-800, for example). The opposite direction, ANU, would be unaffected and should work just fine, even when you are trimmed AND outside the designed range for manual electric trim.