Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Troubleshooting
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Provided Assistance; Aircraft Equipment Problem Dissipated; Flight Crew Requested ATC Assistance / Clarification
ATC Equipment / Nav Facility / Buildings
Our aircraft received radar jamming activity from military assets for approximately 30 minutes beginning approximately 400 nm NW of St. George; Utah while in cruise flight. This continuous jamming activity resulted in multiple aircraft system failures that I will document below. The first indication of jamming activity was the appearance on multiple colored radar 'strikes' on the Nav Display of both pilots during this activity. I have seen this activity before on multiple flights neat military airspace North of LAS; and it always manifests as a display of spiked; multi-colored returns on the Nav Display when radar is turned on. These 'spikes' will extend towards the aircraft and stand-out as no other weather returns are displayed.However; on this occurrence; we witnessed the following additional failures. First we lost GPS position on one GPS receiver; shortly followed by the second receiver failure. On POS page of the FMC; GPS-L and  GPS-R; both failed. Next we had displayed on both PFD's 'TERR POS' failure indications. Next; the XPONDER FAIL light was illuminated; and both transponders indicated failed on the control display amber fail light (ATC however said they were getting our returns). Next; both the Captain and FO clock failed to indicate any time on the displays: --/--. This was also confirmed on the POS INIT page on the FMC. Shortly after; the ANP (Actual Navigation Performance) en-route exceeded cruise RNP of 2.0 with amber displays of plus 2.00 and up on both Nav Displays; also confirmed on the POS page of the FMC's.I then asked ATC if they were aware of any military jamming activity on-going; and ATC confirmed that there was. I passed on our failure modes; and then another flight crew stated the same issues affecting their aircraft. ATC Center then stated he would bring this to the attention of the ATC Sector Director. Very shortly afterward; the jamming stopped and all aircraft systems went back to proper indications almost immediately.
Air carrier Captain reported experiencing jamming activity which resulted in loss of GPS position and multiple other system failures. Shortly after the Captain reported the issue to ATC; the jamming stopped and systems returned to normal.