Dude~ said...Seems strange to me that while we plan flight to the nearest minute, most of us record flight tiime in our log books to the nearest 6?!
Um..if you are recording hobbs in your personal flying log then you are not recording time in accordance with the ANO....
Article 129 quite clearly states an aircraft flight time is brakes off to brakes on....so being sat on the pan for 20 mins after engine start shouldnt be going in the log book....
Article 129
(2) An aircraft shall be deemed to be in flight:
(a) in the case of a piloted flying machine, from the moment when, after the
embarkation of its crew for the purpose of taking off, it first moves under its own
power until the moment when it next comes to rest after landing;
or JAR FCL...
JAR–FCL 1.001 Definitions and Abbreviations
Flight time:
The total time from the moment that an aircraft
first moves under its own or external power for the
purpose of taking off until the moment it comes to
rest at the end of the flight.
And whats more....
JAR–FCL 1.080 Recording of flight time
(See IEM FCL 1.080)
...
(b) The record shall contain the following
information:
...
(2) For each flight:
...
(iii) Place and time of departure
and arrival (times (UTC) to be block
time)
On the other hand if you note the hobbs time directly before brakes off - and precisely on brakes on you should be ok. But hobbs time cannot be logged directly.
(Edited to add JAR FCL ref)