Originally Posted by
FRogge
Since I don't have any experience on other jetliners than the 737, can someone explain how trim runaways are sorted out on aircrafts that doesn't have a trim wheel at all. Personally I think that trim runaways happens so rarely, that once it's eliminated that MCAS can't trim full nose down anymore, I would not be to worried anymore to get on a MAX plane.
FBW planes like A320 and newer and B777 and newer have much more redundancy like several FCC with several channels each continuously comparing their output with each other, possibly more than one motor driving the jack screw, more than one signal path to the motors etc. In sum this makes it exceedingly unlikely that a runaway can happen. Think at how unlikely it is to loose both engines over water far from nearest airport on a two engine aircraft. It is not guaranteed it can never happen, but the likelyhood of it happening is so exceedingly small that the risk is deemed acceptable.
Edit: On FBW aircraft like the A320 there is no significant force required to hold say full aft stick, so less physically demanding compared to the B737 where a pilot might need to use all his force just to hold against a badly mistrimmed stabilizer. Further the elevator on say the A320 is much larger as a percentage of the stabilizer so the elevator has significantly more authority to hold against a badly mistrimmed stabilizer. In sum all these differences make the B737 much more demanding to controll when the stabilizer get significantly out of trim, and the likelyhood of it running away is probably also much larger.