BGRing
From my dim and distant past, flying the AB205A in the Omani Air Force back in the late '70s, I seem to recall that the N2 or free turbine gauge was calibrated in RPM, not a percentage. The usual operating rpm was, (and anyone feel free to correct me here), I think, 6600! This may account for a slight memory lapse by your former Aus Military friend.
Great machine to fly, too.
