Air carrier flight crew reported GPS interference over Europe. GPS did not regain function after exiting area of interference.
Synopsis
Air carrier flight crew reported GPS interference over Europe. GPS did not regain function after exiting area of interference.
Narrative
Departed ZZZZ AT XA:30/XA:59. Our route was planned through many known GPS interference areas. We referenced the GPS company document to review the procedures set forth to safely deal with known or suspected GPS interference areas.Approximately thirty minutes after takeoff; at AT FIR (SOFIA-LBSR); we followed the steps in the document to prepare to fly through areas of suspected GPS interference. The GPS was left off till XIDMI (SWEDEN-ESAA); exiting Sweden airspace. While the GPS was selected off per the procedures; ANP increased to 2.45; ADSB-IN was INOP; and we received numerous other EICAS messages. Between ADOXO and KARTI; the UTC clock advanced mysteriously about 5 minutes. When we exited Sweden airspace; we selected GPS on as per the company document but the GPS never recovered functionality. CPDLC would not function and all position reporting had to be done verbally throughout the flight and an additional report of our times being in error of approximately 5 minutes also had to be relayed to ATC as we continued to use the FMS times in our reports without attempting to adjust them to actual for consistency and since we did not know if that would further complicate the issue with estimated fix crossing times later in the flight. We also had to select GPS to TERR OVRD during cruise due to erroneous audio alerts when totally in the clear of terrain and weather at cruise altitude.Entering Polaris airspace; we logged into ENOB. Auto position reporting still did not work. At this time I went on my scheduled break for the next 3 hrs of the flight until 1 hour before landing and the following narrative is what was relayed to me by the other crewmembers.CPDLC was intermittent till DARUB when entering Edmonton. CPDLC still did not send position reports. Montreal was never able to receive our CPDLC position reports and used voice. During the flight through Canada; ANP grew to over 11. When we switched to KUSA; ANP flipped back to a normal number under .4. I returned to the cockpit about this time after my break and was briefed on the ongoing issues and worked with the crew to set up for descent and approach at this time.We accomplished the GPS Interference Checklist on the Electronic Checklist (ECL). We used GPWS TERR OVRD on approach.Some of the EICAS messages we received during flight:NAV SINGLE GPSSAT VOICE LOSTNO LAND 3ADSB-OUTSINGLE GPSFMS Datalink INOPTERR POSAfter turning off the GPS; it never recovered a useable position.
Second reporter narrative
While on break; per a company document; the Captain and First Officer (FO) turned off the GPS since we were flying through suspected areas of GPS interference. When I came up from break; they had already done the procedure to turn the GPS back on. However; it never recovered. We then followed the guidance and eventually shut them off again per the checklist. CPDLC did not function at all until DARUB where we actually got signed on; but nothing would send. It was in Montreal Center where we could finally send and receive via CPDLC; but automatic position reports still would not send. We also received a GPWS Terrain caution while at FL330. The ANP went as great as 11.1. Once we got in range of VOR DME; it dropped to .46. Some EICAS messages we had included NAV SINGLE GPS; SAT VOICE LOST; ADSB-OUT; TERR POS. After the initial preemptive shut off of the GPS; it never recovered for the duration of the flight.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.