[FabHK]

Still, to have a system on board that, with one sensor malfunctioning, repeatedly trims you down (unless you switch the cutout switch or physically arrest the trim-wheel), is pretty tough.

By the way - in small airplanes, you can overcome trim with elevator pressure. That's not necessarily the case on a passenger jet; and not only because it's much bigger, but because the trim works differently [1]. I wonder whether that played a role. I must admit that before I read [1], I had assumed that bad trim is something I can overpower, when push comes to shove.

[1] https://www.skybrary.aero/bookshelf/books/2627.pdf

[danielvf]

Yeah, when the trim is a giant screw changing the angle of the whole stabilizer, rather than just a little tab, it's a whole different ballgame.

There are plenty of single components on an airliner whose failure can cause a stabilizer trim runaway. Different airliners handle it differently. On a 737 can you can cut out automatic control, and use wheels connected to the stabilizer jackscrew with metal cables. On other airliners, you can cut out automatic control, then switch second electric control system and use it manually. A 737 stabilizer runway isn't an instant thing, and is a loud event in the cockpit.