Hunt for Jet Switches to Visual Search as Radar Empty - Bloomberg
The engineers at Inmarsat were able to validate their estimates of the plane’s location by matching its position at 1:07 a.m., when it sent a burst of data through its Aircraft Communications and Reporting System, McLaughlin said. That final transmission on Acars included a GPS position that was used to calibrate the other estimates, he said.
Does that mean, the final ACARS transmission was already made via SATCOM?
If the ping at 1:11 was used for calibration, wouldn't it have been better to do the calibration against the position from secondary radar at 1:11. Transponder was switched off at 1:21.
That statement only makes sense if ACARS at 1:07 already went via SATCOM, which would mean ACARS via VHF was deliberately? disabled before.