Air carrier flight crew reported a course deviation during departure on the KILNS5 SID resulted when the GPS dropped two fixes and sequenced incorrectly. Reporters stated that ATC reported this was a common occurrence over the past year and the cause was unknown.
Synopsis
Air carrier flight crew reported a course deviation during departure on the KILNS5 SID resulted when the GPS dropped two fixes and sequenced incorrectly. Reporters stated that ATC reported this was a common occurrence over the past year and the cause was unknown.
Narrative
We put in the route at the gate with runway 36C and the KILNS departure to AUDII. We both verified the route. On pushback they gave us 36R so we swapped over the runway transition in the box and verified takeoff numbers for the right side remained the same. We briefed the now right hand turn to heading 225 and verified the first fix to be MUNBE. We took off 36R; made the turn and ATC gave us direct LILIC which we had in the box. The just after checking on with center ATC asked us which fix we were headed to. This was just after KILNS and we were now direct to QUART. ATC explained we missed a departure fix and this was a common recurring problem. At this point we realized the transition on the kilns departure after KILNS had dropped out; probably when we did the runway change. It was weird because all the initial fixes were good we were just missing DURST and AUDII. ATC explained it was a common problem that's been occurring for the last year and they are trying to figure out why we are missing these fixes.
Second reporter narrative
We were cleared to EWR from CLT as filed; with the KILNS5 RNAV departure. I loaded the flight plan in the box; expecting to depart Runway 36C; and the Captain checked the box to confirm it was entered correctly. Upon pushback from gate XX; ramp advised us to expect 36R for departure. The Captain immediately updated the MCDU to reflect a 36R departure and reloaded the KILNS5 SID. I confirmed on the RTE page that we were now setup for 36R with the KILNS departure. We departed 36R and were assigned a heading; then shortly after given direct the first fix on the departure of LILC. The GPS then sequenced us to KILNS as expected; but then instead of transitioning to DURST; the MCDU sequenced us directly to QUART; the first fix after the SID ends. For some reason when we reloaded the departure with 36R; the MCDU dropped the fixes DURST and AUDII off of the SID. Before we realized that those fixes had been missed; Washington center asked us what fix we were navigating to; and we told them QUART; when we now realized we should've been going to DURST.ATC told us this was a common issue that has been happening on this departure and encouraged us to file this report.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.