Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 4
Confusion
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Procedure
I assumed control of the sector approximately 5 minutes prior to discovering this issue. The previous R-side controller was still present when I saw this. Aircraft departed ZZZ-ZZZ1 according to the pilot they were cleared to ZZZ1; however the destination that I was shown was ZZZ2. When I saw the aircraft free-tracking I questioned the previous R-side and asked if he had turned the aircraft for traffic prior to me working. He stated negative. The aircraft was approximately 40 miles north of his route to ZZZ2. I asked the pilot if they were direct ZZZ2; the pilot stated they weren't going to ZZZ2 they were going to ZZZ1. I told him that I showed his destination was ZZZ2. The pilot stated that they had two flight plans in the system; they were originally supposed to go to ZZZ2 but they changed it to ZZZ1 and that's what they were cleared to on departure. The aircraft's route line showed him leaving my airspace to D46; the actual aircraft was heading for D18 and then to D46. I updated the route back to ZZZ2 while this was going on to progress the flight plan to D18; once realizing the error when the aircraft departed I re-cleared the aircraft to ZZZ1 and changed his destination to show the correct destination; and immediately handed it off to D18. When researching this incident; a search on the aircraft showed the route was updated three separate times; since it departed ZZZ. The aircraft traveled 850 miles before this error was finally discovered. This was a particularly dangerous situation because ZZZ2 and ZZZ1 are only 35 miles apart from one another; and even though it was only 35 miles apart the difference in MEA's from ZZZ2 to ZZZ1 is 1000 feet. According to ZDV ZZZ2 MEA is 080 and ZZZ1 MEA is 090. Also there is no STAR for ZZZ2 that we issue however there is one for ZZZ1 that takes the aircraft northeast away from the two DEN RNAV arrival streams where the aircraft are descending on their own. Aside from that if the ZDV controller descended the aircraft to the MEA for ZZZ2 of 080 and the aircraft flew past on the way to ZZZ1 with an MEA of 090 controller flight into terrain; or a cell phone tower could have occurred.
Controller questioned pilot about destination after he saw the aircraft tracking north of anticipated track and discovered two flight plans on file.