Originally posted by putnik
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The "pings" were being heard seven hours later. The ACARS unit was sending regular bursts of data every half hour or so, the last being 0107h. If the satcom stopped working at 0121h, I suppose future ACARS data stopped too, being dependant on the other system. These pings must be something else?
The only thing that ACARS is dependent on is a power supply. The ACARS box on this plane probably used a pair of Airinc 429 connections to the plane's avionics LAN (not to be confused with the 3 ARINC 629 data busses used by the fly-by-wire system -- sorry, no Wikipedia entry for this, and Airinc charges $hundreds for their papers), and probably a simple computer-style serial link to the satcom radio. It's those Airinc 429 connectors that former NTSB "go team" leader John Cox was referring to today. Cox and fellow NTSB alum Gerg Feith appear in numerous aviation-related documentaries, and have been commentators for NBC and other networks during this event. Their credentials are sterling, and what either of them say on the record can be considered to be authoritative.
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