BEagle makes a suggestion and I would like to make a counter suggestion.
Flying instructors are P1 when
- When delivering a structured lesson in a course of study directly concerned with the obtention of a license or rating
- When delivering the 1 hour of training required under JAR
- When delivering structured training requested by a pilot and where the syllabus is briefed on the ground and taught in the air
In all other cases, the FI is a passenger.