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ACARS time

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Old 18th Nov 2004, 20:50
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ACARS time

Where does the ACARS source its UTC time update from?
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Old 19th Nov 2004, 07:46
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Cool

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.
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Old 19th Nov 2004, 08:45
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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.
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Old 19th Nov 2004, 10:17
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Possibly out of date now but on the B744 it used to come from the Capts clock, i.e. as in Spanners post.
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Old 19th Nov 2004, 11:15
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737 'classic' is, I believe, the same. NG from GPS time.
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Old 20th Nov 2004, 23:15
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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.
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Old 21st Nov 2004, 06:31
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Anyone ever seen an ACARS manual ? Online ?
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