ACARS time

[lambsie]

Where does the ACARS source its UTC time update from?

[spannersatcx]

I've had a quick look at the 744 manuals and wiring diagrams, it's not 100% clear but ACARS gets it's time input from the CMC, the wiring diagram shows that the CMC gets an input from the flt deck clocks. As far as I know the clocks are set manually, but this is not accurate as it is a manual input. I would hazard a guess that there is some input from SATCOM which will be more accurate, I just can't find the input at the moment.

[Earl Hadlea]

I believe airbus GPS equipped a/c use GPS satellite time based clocks. This is the time seen on the main panel clock provided the selector is to GPS. ACARS uses this as the time reference.

[BlueEagle]

Possibly out of date now but on the B744 it used to come from the Capts clock, i.e. as in Spanners post.

[BOAC]

737 'classic' is, I believe, the same. NG from GPS time.

[Sqwak7700]

Sounds like somebody's trying to ge paid early ....

In the plane I used to fly it was GPS time. The one I fly now, I think it is taken from ARINC as the ACARS talks to the comm towers.

But you can input a manual time, drop the hammer, and then 5 seconds later the time resets to ARINC time. But the OFF time captured is the manually input time.

[dusk2dawn]

Anyone ever seen an ACARS manual ? Online ?