We may need to go back to the AOM and AD to confirm exactly what the exact wording was, however, the system logic, flawed as it was, would not be unrecoverable if the crews had been given enough information to counter a runaway trim in the first instance with a manual trim input to ensure that the trim returned to a normal range, before the STAB CUTOUT SW....... CUTOUT was selected. If the first action was to go to CUTOUT before putting the aircraft into an "in trim" condition, then, yes, it was possible that the speed, trim and residual elevator authority in conjunction with the minimal torque available by the manual trim wheel for a severe out of trim case, would result in a stabiliser that would overpower the manual trim system unless the elevators were unloaded, a technique which is pretty exciting for the passengers and pilots alike to see the world big in their windows. IIRC, the AD included comments related to being in trim, but did not at any time expand on the criticality of that action, and the industry awareness of the limitation of 60's accepted trim architecture that barely had a fully compliant backup in the absence of the knowledge related to being out of trim v manual trim torque constraints.... this was an ill considered document, and had potential to result in a bad outcome, blaming the ET302 pilot for merely being a pilot and not being Tex Watson is hardly the standard of excellence that the Old Boeing, pre contamination with MDD management, "The New Boeing" the one that sacked QA managers for doing their job, that managed systems that resulted in fasteners on the B787 being a different size on the east coast and west coast... (Coriolis?) who gave the MCAS, the KC46 debacles, VOL I and VOL II, and generally messed up a proud company... yeah.
Yep, it WAS recoverable, when diagnosed properly right away (IE, just upfront know what was going to happen, the yearly sim session). Diagnose fast and react fast, and the official Boeing procedure would work. Be not 100% prepared (and as such react slow), things get hairy. When the AP drops out, together with the cockpit cacophony, things get confusing right away, and it is pretty likely, an out of trim situation will not be the first priority (normally only a nuisance, though requiring attention to get a proper trim balance), to correct. And once you have 20 kg out of trim yoke force, it takes a lot of trim time to get neutral. Combine that with the picky situation, that the B737 nicely goes easily way out of trim in the other direction (Rostov-on-Don) and it is certainly understandable, that all but very experienced pilots are hesitating to keep trimming (The Lion air 2-nd attempt and maybe ET302 too).
We should not forget, a Parkinson alike trim usage would save the show, though that was left out of the Boeing documentation, maybe, because it was unknown, or just, because that would bring a significant change in the trim-computer to light and require the additional training ?
The weasel words applied did not make it easy for a crew confronted with a change that was very recent and which had not been trained or explained in depth to the flight crew.
The evidence is that of the 3 events, the one the sector prior to Lion Airs splash, and the ET302 one, where 2 of those beat the driver, and one driver set had the new instructions, it would seem to have been quite reasonably, nay, necessary to go back and sort it out at fort fumble.
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All Corporate management of TBC since 1995 bears responsibility for the damage imposed to the engineering reputation of that company, and should be held accountable, their actions damaged shareholder value and there was repeated evidence that they were heading into the weeds in their myopic management practices.
Yep, how to make a company great again, get Trump style leadership !