This is not true. In the condition of a failed AoA vane like on the two accident flights, there is no way to enable the trim thumb switches and disable MCAS.

This is not true. In the condition of a failed AoA vane like on the two accident flights, there is no way to enable the trim thumb switches and disable MCAS. You either get no electric trim and no MCAS or you get both. If you happened to have known that MCAS pushes the trim down for 9.3 seconds and then pauses for 5 seconds, you might have been able to time it and turn on the electric stab trim at just the right time when MCAS wasn’t trying to kill you, but unfortunately the very existence of MCAS was hidden from pilots. If you flip the stab trim cutout switches, you can turn the wheel manually, but if there have already been a couple of cycles of MCAS, the plane may be so out of trim that you need too much force to move the trim wheel manually. In that case there is one thing that could save you which would be to do the so called rollercoaster procedure, where you push the yoke forward to unload the trim and then crank the trim up while you hurtle towards the ground. This was a documented procedure in the 737-300 manual, but was later deleted. The real crime was that Boeing deliberately removed all mention of MCAS from the flight manual. The problem was that if there were procedures that pilots needed to know in order to recover from an MCAS failure, they would have been required to practice these procedures in a simulator, and Boeing’s contract with Southwest had financial incentives if the MAX didn’t require any additional sim time for pilots to transition from the NG to the MAX. We know that the information about MCAS was deleted from the manual because the only occurrence of the term MCAS in the MAX flight manual is in the glossary where it is a defined term. The tech writers obviously put it in there because it was described in an earlier version of the manual, but later deleted, but the glossary entry wasn’t deleted when the description was.