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.”
Also see the ‘forceful‘ arguments in
https://www.satcom.guru/2019/04/stab...and-range.html
Where the Equivalent Safety Case relates to normal flight with an aircraft reasonably in trim - low tail forces - Peter L, initial diagrams with level tail +/- elevator.
However with serious trim malfunctions, the tail displacement together with adverse elevator load attempting to recover, might limit electric trim (latter diagrams). Add effects of elevator feel offset due to false stall warning, higher stick loads add to trim offset loads.
Discussions range between trim motor stall, and/or trim inhibit at large angles for trim runaway safety case.
Also remember that MCAS vs elect trim is 10 to 5 time ratio in favour of nose down.