CNN The Situation Room December 29, 2014 22:51:00
Not only does it record all the vital information that the flight recorder normally gathers, it can intercept that information, and track it and start transmitting. these signal also go to the satellite, override all other traffic. they'll get a priority that's the protocol. so between the time that something happens to a plane, as in this case for example, and when it hits the water, if that's what it ends up doing, it will already have a lot of data and tell you what went wrong in that plane. you will also have where it went down in the ocean. the idea that this will take another five or ten...
Source: archive.org