avspook said:
Its can be programmed for number of retries - This is the VHF ACARS they are talking about, on some AB's will ahve a dedicated provider eg SITA however you may alos have the option to swicth to another provider (Arinc) however it will keep interrogating the SAT until it offload its message.
The company i worked for the VHF had 3 goes at offloading the ACARS before switching to SAT , It figured if it missed 3 offloads it must be out of range of a Line of site VHF station & then switched to the more expensive SAT option.
No HF mesgs - no hf fault same for engines same for Inertial Data from the ADIRU teh ACARS Hit the SAT... It knew where the aircraft was (lat long) it knew where to find the SAT and it beam steered the Antennae to get that hit
at the Maintenance center for both Boeing (Aircraft Health Management option) and airbus (AirMan Option) the messages will pop up allowing access to order parts send repair info to the arrival station while the aircraft is in flight. The LAT/LON of the aircraft also used to show on the screen and on the AirMan option you could view a realtime globe of your fleet
This is very important. So, from your expertise, Behavior of ACARs transmissions is largely customer (airline) specific. Most airlines would avoid exclusive SAT transmissions unless they like big monthly bills. But in the mid-Atlantic, after the MU (or it descendent) gets tired of trying VHF (out of range) and then maybe HF, THEN it would reference it's spacecraft almanac and drive the Sat antenna to the GEOstationary sky coordinates and attempt to blow the whole message up at once. Right? Without a sucessful response from the Satellite, it will start over and attempt repeated interigations of the spacecraft,
until it gets a response.
This is important because, if it is true (and I'm taking it on rumour that those coordinates were part of the message at 0214z), this means that the IRU portion of at least one of the ADIRU's was functional.
Why is this important, you ask?
Because if the crew had an IRU platform at 0214z, (and they had to for the ACARs to broadcast it's position to the Satellite),
then they likely had Attitude information available to them.
This strongly suggests to me now, that the airplane was wings level at 0214z completely intact and flyable in Alternate Law with attitude information available. (This does not mean, by any means, that any pilot could have kept it right side up in that kind of weather system.)
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