It's very hard to solve one problem without creating another. At some point, you just gotta trust the pilot.
MCAS was basically made to prevent user input that would send the plane into a dangerous angle. The computer overrode the inputs. So there’s precedent for something like it.
This is incorrect. The manual stabilizer trim thumb switches override MCAS.
MCAS affects the stabilizer, the thumb switches affect the stabilizer, the cutoff switch affects the stabilizer.
The elevators are controlled by the control column and the autopilot.
> The trim switches override MCAS, but when released, MCAS can resume trimming down again.
That is correct. That is why the procedure is to return the trim to normal with the thumb switches, then turn off the trim system. That's it. That's all there is to it.
> but they can make the controls so heavy that it's impossible to pull up.
Almost right - the trim has more authority than the elevators. The trim's ability to travel far is to provide great ability to get out of trouble. I don't really know what factors the aerodynamics guys used to calculate the max travel required. I do know there is a travel limiter on it (as I worked on that, too!) which reduces the max travel at higher speeds, because otherwise it can rip the tail section off, which is a big no-no.
There are sooo many constraints on the design of an airplane I sometimes wonder how anyone manages to make one that works at all. The Wright Bros calculated that their machine would fly, and it did, barely. Their contemporaries did seat of the pants design, which is why they failed.
The Wright brothers succeeded because they were pioneers in wind tunnels and aluminum engine blocks.
Thank you, I'll update my brain and future explanations. :)