I just need small clarification regarding twinjet:
During one engine run -up at high power in a TWINJET, does the MM state that the opposite engine should also be run-up?
yes on twin jets (airbus again) you bring non test engine up above idle to balance thrust. I have heard stories of an early A320 doing a high power run on one engine with very little fuel on board and the aircraft turning on the spot.
I also find leak detector spray and tin foil methods ok in 95% of tests again just takes a bit of time to get right.