I didn't read the whole thread but this question came up today. I thought it was the classic definition of "movement under own power for the purpose of flight"
I was wrong.
In Canada at least its
Background
CAR 101.01(1) defines "flight time" as meaning "the time from the moment an aircraft first moves under its own power for the purpose of taking off until the moment it comes to rest at the end of the flight".
For aeroplanes, the meaning is clear and for helicopters that can taxi on the ground, "flight time" is interpreted as it is for aeroplanes. For helicopters on skids, it has been interpreted to mean, "skids off to skids on". In this case, "flight time" and airtime would be the same.
Annex 1, Chapter 1, of the Convention on International Civil Aviation sets out separate "flight time" definitions for aeroplanes and helicopters. For helicopters, "flight time" is "The total time from the moment a helicopter's rotor blades start turning until the moment the helicopter finally comes to rest at the end of the flight, and the rotor blades are stopped." In Canada, some have applied the ICAO definition of the helicopter "flight time" for helicopters on skids.
Action
In order to clarify the interpretation of the definition of "flight time" with respect to helicopters as it applies to flight crew licensing, "flight time" shall be as it is set out in Annex 1: "The total time from the moment a helicopter's rotor blades start turning until the moment the helicopter finally comes to rest at the end of the flight, and the rotor blades are stopped."
In order to align formally with the Convention, a Notice of Proposed Amendment proposing a separate definition for helicopter "flight time" will be presented to the Part I Technical Committee.