My 2p...
60 years is not far enough into the future. They would squark 7600 for radio failure and broadcast on 121.5.
We are still using equipment and procedures from 60 years ago so why would there be a radical change in the next 60 years?
d=st
We have distance travelled, we have ground speed and we have time so there can be no discrepancy to extrapolate. Maybe if you lost a variable that might help.
(edited for spelling)