"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"
Engine on (aircraft IS moving under its own power), Rotors turning (for the purpose of flight), until the moment it comes to rest, (Engine off, Rotors stopped).
As a PPL I dont climb into the helicopter for any other purpose than for flight, Im sure maintenance logs reflect further hours for the aircraft, although as I dont partake in ground runs or sitting on the ground burning money I dont log that time anyway.
However, I as the pilot in the cab starting and shutting down the aircraft is part of the flying experience (I cant get airborne without the engine or rotors turning) therefore it is for the purpose of taking off.
Must admit I dont check my watch until I actually lift and that is the time I put in my log book, I will however look at using the Datcon as its bloody expensive waiting 2 mins run up and 2 mins run down I could be logging toward my CPL...
IMHO, if that aircraft is running, its in a dangerous state and that requires a pilot with hands on if he/she is hands on then he/she should log the time.
Great thread which seems to have got everyone thinking.