Responding to mpyne: you can envision scenarios where the fire took out their radios.
TrevorJ is a lot closer to the mark, although it wasn't the engine system phoning home, it was some sort of generic hourly "ping" with no other content (since the airline didn't sign up for the service that would have done more). Since these were pings from or to IMARSAT geosync satellites, very rough estimates of where the plane could be have been were made from them. I assume based on which satellites heard them (vs. ones over the horizon), perhaps comparing time-stamps and transit times to 22,000 miles in orbit, etc.
But of course the bottom line is that these pings went on for hours, which evidently would only stop when the engines stopped for whatever reason. That makes a plausible fire scenario more complicated.
TrevorJ is a lot closer to the mark, although it wasn't the engine system phoning home, it was some sort of generic hourly "ping" with no other content (since the airline didn't sign up for the service that would have done more). Since these were pings from or to IMARSAT geosync satellites, very rough estimates of where the plane could be have been were made from them. I assume based on which satellites heard them (vs. ones over the horizon), perhaps comparing time-stamps and transit times to 22,000 miles in orbit, etc.
But of course the bottom line is that these pings went on for hours, which evidently would only stop when the engines stopped for whatever reason. That makes a plausible fire scenario more complicated.