StormyKnight
Why is everybody assuming the comms was from ACARS?
I presume, that if it is switched off, it is off, i.e. no polling or handshaking with a ground station or satellite?
I also presume that whoever was flying the a/c would need to communicate with a ground team somewhere where they were heading. That would need SATCOMs, surely?
Is it beyond possibility that the signals picked up by the satellite(s) were voice comms between the 'pirate' and a ground team?
I can't see the 'pirate' just swanning off in the plane without a support team somewhere to help with getting the a/c on the ground. That team would have no way of knowing if the op was a 'go' unless the 'pirate' could communicate with them, would they?