Regarding comments that existing (and fitted) technology is already available for tracking aircraft at all times:
But is this equipment currently powered when the engines have flamed out? Satcom transmission invariably involves boxes which tend to use up a lot of power (and therefore are usually omitted from the list of things usually powered when the main electrical busses fail). Some aircraft don't even have standard ATC transponders powered when the aircraft systems are running on Standby or HMG/RAT power.