Ascot BZN
The way (Ascot) cacl'd mvt times were not as we (civil) did.
Trad way which still applies to most operational applications are:
A flight commences/terminates at Off Blocks/On Blocks (Brakes Off/Brakes
On) Published schedule times are basec on these times.
Flight time is cacl'd form wheels off to wheels on.
Doors closed/opened is a specific pax handling/traffic application.
Too simple really, there are so many interpretations operationally, but for pax ops the IATA terms are applied.
PS. I wasn't Ascot, but involved with BZN & the Truckers @ LYE