An old training capt once told me min 40% on app for spool up reasons alone! Maybe the Lawers got involved.
That sounds like yet another old furphy propogated by those who should know better. No warning in the FCOM about 40% N1 spool up unless you are talking about the initial spool before pressing TOGA at the start of the take off roll. And that is for a different reason altogether.
In another life there was a company procedure designed by our chief pilot that we must never come below a certain approach power setting on final below 1000 ft. It was an an F28 and to do with the chief pilot's personal opinion on spool up times in case of a go-around.
While under line training I needed to reduce thrust a smidgin to adjust speed on short final although the glide slope was spot on. The checkie screamed at me that I was breaking company SOP by bring the throttles back below the magic spool up number introduced by the chief pilot.
I said no problem - in that case I am now going around. Don't go around for fukc sake screamed the checkie- just don't do it again..
