Mayday
I don't suppose it would be difficult to have a beacon that ejects from the plane *before* it crashes. If you fed the flight data into something as small as a Rasberry Pi surely it could determine several easy parameters.
For example if roll, pitch or yaw exceed normal bounds
Airspeed increasing
Less than 1000 ft altitude
Landing gear not deployed
Engines not functioning or at full throttle.
Then eject an EPIRB with a parachute attached. (parachute for crashes on land) A clever system would squirt a sub-set of the black box data into the EPIRB before ejection.
https://en.wikipedia.org/wiki/Epirb