Originally Posted by
lemme
If the flight crew knew where they were (assuming ADS-B reports are correct), then they still had 5,000 feet to the FAP in about 10 nm (or about 1,000 fpm).
The fact that the ADS-B data being sent was subject to inertial drift doesn't necessarily imply that the crew didn't know exactly where they were. I haven't seen any suggestion that while they were flying the hold, prior to it all going quiet, they didn't have a working VOR/DME. (Well OK, the RNG DME could theoretically have been sending duff data, but Occam's Razor applies here).
It's analogous to an observer using ADS-B to monitor the height of an aircraft on approach, forgetting that it's displaying QNE whereas the crew will be seeing QNH-adjusted height on their altimeter.
ADS-B tells its own version of the truth.