ADFR is a unique system which releases the integrated flight recorder / locator beacon from an aircraft at the onset of a crash and provides improved recoverability over the more traditional 'black box' flight recorder which is, instead designed to survive an impact but remains on board the aircraft.
The improved survivability of an ADFR brought it into many discussions surrounding the crash of Malaysia Airlines Flight 370 (MH370) in 2014 and the subsequent search for the flight recorder.