How much does air pressure vary over a region, and how quickly does it change?
Had they known they wouldn't be able to rely on GPS, all that back and forth with ATC would not be needed, and they'd already have a plan B and a plan C for navigating.
It's unfortunately all slices of swiss cheese aligned perfectly, but I'd still blame the military for poking extra holes on the GPS slice.
medevac flight - there was probably some urgency.
And I am happy to be corrected but as I understand it, in the rural west more medical transport than you might think is by air. Distances are large, and population is sparse. You can cover more area with the same number of medics using a few airplanes instead of ground ambulances. So not all air ambulance service is critically urgent, unlike what we are used to in more populated areas.
One technical point that initially puzzled me was why Spidertrax appeared to retain GPS coordinates while the FMS did not.
My understanding is that certified FMS GPS receivers use Receiver Autonomous Integrity Monitoring (RAIM) and other integrity checks. During GPS jamming, the increased noise and degraded signal quality can cause the receiver to determine that it can no longer guarantee a reliable navigation solution, resulting in a NAV FAIL or RAIM warning.
A tracking device such as Spidertrax, on the other hand being a glorified telematics grade positioning device, is designed for best-effort position reporting rather than certified navigation, so it may continue outputting an estimated position using noisy GNSS data and motion filtering, even when that solution is no longer suitable for primary aircraft navigation.
In any case the news (and ntsb report) points that they are tied, not responsibility.
SRR is serviced by two instrument approaches, the ILS or LOC RWY 24 and the RNAV (GPS) RWY 24. Both instrument approach plate notes section contain the following statement: “When local altimeter setting not received, procedure NA (Not Authorized).”
IFR approach was not possible, the flight plan was unrealistic.
Questions must be asked about how and why we got here rather appeal to submission.