Stone69, climber314,
The speed increase would be more likely (logical) where the focus of attention was towards the indications of low / min speed and stickshake, and possibly UAS.
Re ‘continuous’, no doubt the lawyers will play with words, but MCAS’s 10 sec on and 5 sec off is not continuous - it’s cyclic.
The preceding flight associated the trim movement with STS, a normal function, but the crew did identify an incorrect direction; thus after investigation, flap cycling, the trim was disabled. Tech log ‘logicaly’ associated the STS problem with speed disagree.
There is nothing in these actions, lines of thought, which would be given to the accident crew, who effectively started agin after maintenance on speed / AoA related issues.
In all of the flights the MCAS was operating as designed. It was the failure of a system input (AoA) which caused inappropriate trim movement, and several significant alerts which distracted from the problem.
Technology worked as designed, but the design did not work for the pilot in the event of a minor, un-annunciated input failure.
Furthermore, these issues could be reflected in maintenance. All reports and crew discussion guided fault finding towards speed / AoA, feel, and Speed/Mach trim. The relevant systems were checked/changed.
Ground test would be difficult; MACS trim only operates in the air, with flaps up, with the controls powered, and the control column unloaded. AoA input depends on the vane position, logically identical on the ground/no airflow, thus MCAS could have tested as designed (we don’t yet know if the physical vanes were split or just the electrical signal).
And who would know about MCAS? Pilots have a differences course; no new/changed drills or actions - info only, except there was none. Does maintenance have a difference course, is this mandated, what information would it convey?
Thanks iff789, - reset, if so then a ‘standard practice’ of swapping / changing sensors to aid fault finding would be worthless - self defeated by the BITE check ( which presumable did not provide and help). A ‘wicked problem’ to solve.