Air France Flight 447 Acars Data
Acars is the wireless data system that planes use to relay information about their general state of health to ground stations. In a scenario like that with Flight 447, it can give clues to the sequence of events that build-up to the tragic loss of the plane,crew & passengers.
Acars transmits data at 1200 baud over a 131.725MHz radio link. It can be received on a regular PC using the headphone socket on an Airband radio connected up to the Line-In socket on your PC’s soundcard. You then need to download Wacars software (the Wacars site also contains a very thorough description of how the system operates).
If you don’t want to go to these lengths to see some Acars data you can go to this Virtual Air France site instead – it shows markers with flight details overlaid on a Google Map (it even lists the captain’s name!).
I read some time ago that the Americans were pushing to get the Acars system updated to use some digital encrypted transmission standard, i’m not sure how far this got? At least the current system is transparent!