That may be true, but the "Satellite coms" don't talk directly with the Satellites. They talk to a ground station that relays the information up to a satellite, so if the aircraft is out of range of a ground station, the messages won't go through that system.
Er, are you sure?
What would be the point?
AFAIK satcom is used when out of range of VHF. EG over mid atlantic. The a/c communicates directly with satelites.
https://www.google.co.uk/search?q=ai....0%3B581%3B526