NavList:

Hello to all,

I concur about the "Military use" of this expression, at least in the US Navy a few decades ago.

When on the [USN] Aircraft Carrier decks we always needed an accurate "Common Time Reference" before launch because for the subsequent onboard recovery each Section/Division Leader was to start his own overhead breaking turn at a specified time (+/- 30 seconds of time) . If not given any "Time reference" earlier during his mission briefing, any Pilot to be launched could and would request "Time Hack" on his radio shortly before launch (to be sure that a maximum number of other fellow pilots would be monitoring Tower frequency then, so as to minimize such "Time Hack" requests), and the Carrier Control Tower would broadcast the Aircraft Carrier Own Reference Time. We could then afterwards refer to the same time reference and very importantly also arrive overhead exactly on time for the recovery. With reasonable care and training, leaders would start their breaking turns within 5 seconds of the published times.

Now with widely disseminated wrist choronometers accurate to a tenth zillionth of a second, I doubt whether our "Time Hack" familiar calls can be heard so often ....

Kermit