Originally Posted by
FrequentSLF
Not a pilot
still I wonder why the MAX needs a PRI and B/U cut off! Forget the label changing, what surprises me, is that on a new design the two switches are in connected basically in series, and either one is doing a cut off! Means the previous design was faulty? And in the new design was considered safermto have a back up cut off switch, just in case the primary fails? What kind of engineer will design a system with a single sensors, single computer, single motor to drive a flight control, and feels the need to add a back up cut off?
Well, that is precisely the point: It is so unreliable that you want to make double sure that it can be switched off. Being able to switch it on is not guarded by a backup switch.