Originally Posted by
Luc Lion
It was a great idea to have 2 cutout switches (up to the B737 NG) ; one acting on the yoke trim switches and the other acting on the autopilot and STS.
It was a not so great idea to replace them with a primary cutout switch and a backup cutout switch, both switches acting on both electrical channels of the trim.
This^^^ (my emphasis). If the actual change to the trim switches didn't threaten the manufacturer's certification strategy, I wouldn't expect that doing the sane and sensible thing -- disabling HAL's electric trim authority (STS, AP and MCAS, together or separately) while leaving the pilots' alone -- would be a problem. So, why . . .?