bunk exceeder
SARSAT/коспас seems not to have been mentioned. Why wouldn't it be able to pick up the 406 MHz ELT in a 777 were one to go off?
IF the ELT went off, then Sarsat MIGHT pick it up. The system is not flawless, on both the beacon and satellite sides. There has been no mention from the authorities about an ELT signal, so presumably a signal has not been received. When a signal is detected, alerts go to multiple locations, so there isn't a concern that someone somewhere missed the alert.
Mike