Originally Posted by
reamer
It's supposed to when the autopilot is on and after takeoff when the autopilot is off and the flaps are not up.
When you are reading erratic indications on your instruments and it is consistantly trimming down, switch it off, you might save some lives.
And in cruise as you burn off fuel and your cg changed , and when the Mach transducer says so. It’s constantly moving.