I noted on the PFD of a 737NG level-D training simulator, that accelerating the plane in level flight slightly changes the red/black squared VMO/MMO (maximum operating speed) indication on the speed-tape.
My precise observation was that for example flying at FL350, accelerating the aircraft from 250 to 270 kts, moved the barberpole up several knots.
I thought the VMO/MMO should be independent of airspeed itself? Anyone who can shed light on the way VMO/MMO is calculated and how this is in the real aircraft?
ps: I am talking about a clean aircraft. I know that flaps, gear can have effects on the VMO/MMO.