Currently my airline uses data link in remote areas. We are able to "text message" ATC and the aircraft is sending messages to ATC and the company on a schedule I don't even know. (A friend blocked in in Germany and noticed a spare engine sitting on the ramp. While finishing paperwork the German techs came up and asked if they had any problems with the number two engine. "No, why do you ask?" "It called the company and wants to be changed" was the reply he got.)
Anyway all this works great except every once in a while we'll get a system message "Data Link Lost." Then 15-20 minutes later we'll get a message "Data Link Available." What the odds that you'll get tonnes of normal data then when something happens you'll be in some blind spot and not get the data you want?