Narrative:

Our aircraft received radar jamming activity from military assets for approximately 30 minutes [near] 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 near 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 position page of the FMC; GPS-left and GPS-right; both failed. Next we had displayed on both pfd's 'terr position' failure indications. Next; the transponder 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 first officer (first officer) clock failed to indicate any time on the displays; --/--. This was also confirmed on the position 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 position 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.ensure military jamming activity is documented to prevent interruptions to transport category operations.

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Original NASA ASRS Text

Title: Air carrier Captain reported experiencing jamming activity which resulted in multiple system failures.

Narrative: Our aircraft received radar jamming activity from military assets for approximately 30 minutes [near] 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 near 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 TRANSPONDER 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 (First Officer) 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.Ensure military jamming activity is documented to prevent interruptions to transport category operations.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.