The automatic alerts make sense. It’s the absence of manual alerts that seem to indicate something quick and catastrophic taking place.
Nope. Moose4 discussed that here:
It’s a range issue. Aircraft use AM VHF radio communications on the band between 118 and 136 MHz to talk to air traffic control. Those are basically “line of sight”. Now with the plane being up at 35,000 feet, it’s got a heck of a line of sight and that extends the range considerably. You can use a hand-held airband scanner and hear aircraft 75-100 miles away from you clear as day when you can’t hear the tower at an airport just down the road.But this thing was 400+ miles north of the nearest point of land, and that’s just going to be out-of-range for two-way voice comms on VHF. So for over-ocean flights, they use HF frequencies down in the 5-7 MHz range, shortwave. They can travel thousands of miles, but they’re just like an AM radio around a thunderstorm, and they’re subject to ionospheric interference as well. Typically, as I understand it, the aircraft only calls air traffic control when they cross certain points of their flightplan, and they give their location, speed, altitude, and estimated time of arrival to the next reporting point. Other than that, they’re pretty much on their own; there’s no radar coverage, so ATC can’t see them.
The automated messages that got sent back to Air France maintenance were, I’d imagine, sent via satellite. But satellite transmissions aren’t used to talk to air traffic control. That’s all simple radio communications where the technology really hasn’t changed a whole lot in 50+ years.
Lack of manual communications may not be that unusual.