BOAC mentioned:-
It would still be useful to know what data was being sent from Acars via SAT
Perhaps ...
I seem to recall reading on pprune that the engines were leased from RR (power by the hour?) and that RR used ACARS for engine data. Perhaps RR paid for satellite acars for their data?
There would likely be engine start messages, who knows? Once in the cruise no more messages due to stable engine operation?
I forget now, is there some evidence that the satellite acars was turned off or disconnected leaving the bare satellite terminal doing its ping thing? I vaguely recall that there is. Presumably fuel exhaustion would generate some engine acars messages but none were received.
So many questions, so few answers.