Ground running an L1011, after start the throttle was moved just a little, but the engine accelerated towards T/O power; the cut off switch worked fine; RR stated it could not happen, but some months later came back with the FFR strip report that a failure had allowed full throttle internally.
I recall the cut off switches are a simple design much like you would have found in 1960 car dashboards with a sprung forward position for extra cold start fuel flow the guards were simple too, 1/2 moon type fences.
I was surprised from above B J J entry, to learn the throttles need to be retarded so achieve cut off on this Challenger, fire handles are a lot slower in my circumstances.
What need was there for these larger switch paddles on the Challenger beats me!