ABUKABOY - Thanks, I wondered whether rate of change of power demand had anything to do with it, though I would have expected it to be the other way around: i.e. if throttles were slammed forward, I'd expect the prop speed governor to struggle (and hence produce my 70's dip) especially if the demanded speed had changed ; for a slower throttle advance, I'd expect the governing to be much better.
Either way, do you think there might have been a change in BMA's operating procedures recommending a different throttle advance rate between the 70's and 80's ...?
Just curious. Cheers.