B787-9 flight crew reported GPS jamming on their international flight that apparently affected their ADS position reporting; leading to a go-around when the Approach Controller was concerned they were not lined up on the correct runway.
Synopsis
B787-9 flight crew reported GPS jamming on their international flight that apparently affected their ADS position reporting; leading to a go-around when the Approach Controller was concerned they were not lined up on the correct runway.
Narrative
Flight experienced the usual GPS/ADSB jamming/spoofing/malfunctions enroute in at closest points to ZZZZ3 airspace. EICAS displayed 'single GPS' for remainder of flight including approach. We were given vectors for a left downwind and pattern for runway XX L. We were given a northwesterly heading to intercept the runway XX L localizer and cleared for ILS approach. Autopilot captured LOC normally and proceed to track centerline of runway accurately. Fortunately; the visibility was good and I could clearly see the runway centerline lights for runway XXL; we were perfectly lined up on the runway centerline for the entire approach. Controller queried us as we intercepted the LOC and asked us to turn left to intercept the LOC. There was concern in his voice and all 4 crewmembers confirmed we had the correct ILS ID displayed; proper approach loaded in the FMC and visually lined up on runway XX L. I reported to the Controller that we were on the LOC for runway XX L. Controller then gave further instructions to turn left with great concern in his voice. I again reported that we were on the LOC for runway XX L. Ultimately were were told to go around on short final. First Officer flew a very nice go around for a second approach. Second approach was uneventful and we were kept approach control frequency until clearing the runway. Had maintenance meet us at the gate and described the situation to mechanic. It was obvious to the entire crew that the ADS/ADSB position reporting information reported was inaccurate and the Controller had a 'phantom' target for us displayed on his equipment. I made a detailed Aircraft Maintenance Logbook entry. I was able to obtain a phone number for ATC and spoke to the supervisor in approach control He was very gracious and appreciated the call. We had a discussion at length regarding the displayed position of our aircraft on this approach. The supervisor reported that the position shown on his equipment showed us well north of the runway XX L centerline and encroaching on runway XX R centerline. He also reported that our aircraft was the ONLY aircraft showing this position reporting malfunction. This is a serious issue as ATC could vector this aircraft unknowing into other traffic or terrain. Fix the ADS/ADSB.
Second reporter narrative
We were cleared for the ILS XXL and while on final approach to RW XXL in VMC; ZZZZ Approach Controller asked us to verify that we were lined up on XXL LOC. We confirmed we were. Moments later; he repeated his query; with more urgency. We double checked flight deck instrument indications against our selected approach plates in Jeppesen FD Pro and cross-checked those with visual reference to the runway; which was clearly in sight. Relief pilot also confirmed we were properly set up. We again assured ZZZZ Approach that we were lined up properly. Despite our assurances; Controller seemed audibly upset about the situation and ordered us to go around on short final. We complied; executed a proper go-around and received vectors for another ILS approach to XX L. We set up; followed Controller instructions and landed on XX L without further incident. During the second approach and landing; ZZZZ Approach elected to keep us on their frequency until we rolled out on RWY XX L; after which time they transferred us to ZZZZ Tower. Upon gate arrival; CA requested/received a phone contact for ZZZZ Approach Control. A cordial conversation with the approach supervisor indicated that his Controller was receiving erroneous ADS information from our a/c. Controller was convinced we were drifting onto the XXR localizer and in imminent danger of colliding with another aircraft; hence the go around instruction. During the flight; we had received GNSS interference (GPS jamming) over two countries. Only one of our two GPS receivers recovered and we conducted the rest of the flight with the EICAS advisory message NAV SINGLE GPS." Company-supplied information indicates B787 ADS reporting is tied to aircraft GPS receivers. I think that the loss of the GPS receiver due to jamming also caused a loss of accurate ADS position reporting from our airplane. Furthermore; on my last 3 trips ZZZZ-ZZZ; each time in a different aircraft; we have been jammed over Country X and Location A. In each instance; we ended up with the NAV SINGLE GPS advisory. There were no specific indications of ADS trouble. NAV SINGLE GPS was the sole navigational system message visible on the flight deck. Yet; in each instance; oceanic Center gave us major oceanic reroutes during the Radio Communications Link process. On one trip; while on a rerouted oceanic clearance; Center told us to turn off our ADS reporting due to significant errors. Oceanic reroutes induce more opportunity for flight crew error (manual FMS route changes; including half-latitude waypoints); and unplanned diversions (due to excess fuel burn) and crew layovers (due to crew duty time limitations). Additionally; oceanic reroutes appear to cause major inconvenience to oceanic controllers. Conversations with other pilots have revealed similar situations on their ZZZZ-ZZZ flights. I'm not sure what the exact technical fix would be; but it seems that B787 ADS reporting needs to be tied to another system in the airplane; or enabled to be tied to a single GPS. Additionally; NAV SINGLE GPS should be upgraded from an EICAS advisory to an EICAS caution due to the near-certainty of ADS failure or inaccurate position reporting. Aircrews need more visibility to ADS issues resulting from GNSS interference and need more time to plan for or react to them."
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.