I actually had a very good example of this being a bit of an odd one on Sat as I took part in a small flypast at our local field.
As I was first through the plan was a stream takeoff low-level tight circuit and a max chat pass before standard circuit and landing, because of this I spent a good 15mins running the engine up to temp with only approx 5mins actually in the air. So does that mean I can log it as a 25mins flight? IE 15mins run up, 5mins flight and 5 mins taxi in and cool down?
It only went in my logbook as 15mins as I just use the 5mins either side rule I was taught 15years ago. I've had some monumental holds at Aberdeen over the years involving sitting for 45mins on the ground being shuffled around various holds before being able to get off....again, only ever logged that as 5mins either side also....
Regards
UA