Commercial Fixed Wing
Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Troubleshooting; Workload
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Other / Unknown
Aircraft Equipment Problem Dissipated; Flight Crew Overcame Equipment Problem
Airspace Structure; Aircraft
The operating flight crew notified me of a problem while I was resting in the bunk. I went to the Flight deck and they informed me that the NAV Performance system indicating up to a 15 mile ANP. They informed me that they ran through the appropriate checklist. I stayed on the flight deck while the ANP return to a normal value. This only lasted for about 20 minutes. We continued to Anchorage and landed without incident.I suggest we track the locations and times of these events in order to determine whether they are internal aircraft system related or external signal interference related.
GPS R & ADS-B R failed.Between Navigation points UNEDA to NOKID; GPS L remained on and accurate; but was not updating FMC positions. RNP required 4.0. ANP rose slowly to approximately 2.6. After 3 minutes; the ANP jumped to approximately 15.6 then continued to rise slowly. Crew completed GPS R Fail and ADS-B Fail checklists. ANP did not recover from checklist completion. Crew reported loss of RNP capability to Magadan Control.Crew verified position vs navigation reference pages and from radar contact (Magadan) at point BE. The aircraft did not receive an active bearing pointer from BE. The autopilot maintained previous planned track; no navigation deviations noted.Near NOKID GPS R and ADS- B R status messages cleared and ANP rapidly Normalized to 0.08. No further issues were noted.Suspect Active GPS jamming in the area. Suspect system logic problem for L GPS not supplying position information to the FMC's/ANP after GPS R failed.Under radar control flight segments or within range of ground based navigation facilities; verifying an accurate location is a common and easy task.
Air carrier flight crew reported possible GPS jamming resulted in loss of GPS and ADS-B.