Originally Posted by
tawnybird
Whilst we don't know how the 'investigation' looks at this today, we do know that we can't definitively say that ACARS was disabled (neutral term) before the last transmission.
We only know that ACARS did not make it's expected transmission at 17:37. This would place the time of disablement between 17:07 and 17:37.
I do not know if the ACARS logs have been made available. But the ARINC 620 datalink specification has a 'logon/logoff' protocol. If the ACARS 'failed' or had its CB pulled, then there would be no logoff protocol messages. If the ACARS was tidily switched off then it would have followed the log off protocol.
The early statements implied that it had logged off, meaning someone who knew how to find the ACARS menu had switched ACARS off.