Date: 201502
Local time of day: 1201-1800
Location: PRC.Airport, AZ
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Cessna Single Piston Undifferentiated or Other Model
Operator: Government
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Landing
ATC / advisory: Tower PRC
Reporter organization: Government
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Private; Flight Crew Instrument
Human factors: Situational Awareness
Second reporter function: Local; Instructor
Anomaly: Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Detector: Automation Air Traffic Control
When detected: In-flight
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Approaching Airport from the NW at 7;500 MSL; tower cleared aircraft for Left traffic to RWY 3L. Proceeded inbound descending to 6;500 MSL and entered left traffic.  Tower cleared aircraft to land 3L. After rethinking the event; I am sure I read it back correct but for some unknown reason; I was thinking 3R. 3R is the main runway and is the runway I have always landed on when approaching from that direction. I have no further explanation as to why my mind switched to the other runway. As I always do; I cleared the area visually in all directions before making any turns and upon turning final. All my lights were on including the Pulse light. The next communication from the tower was to inform me to take the next available taxi way to the left. To my knowledge; there was no interference with any other traffic in the air or on the ground.


Second narrative: I was training a supervisory developmental on the Local 1 position RWY 3R. The developmental cleared an aircraft that was in our pattern for touch and go. In my scan I looked out to final for RWY 3R and saw an aircraft. I believed my internal clock was off because I expected our number 1 plane to be on base. My developmental cleared the number 2 aircraft and I looked and saw an aircraft on downwind. When I looked onto the runway and visually saw the aircraft land I realized it was not our plane that we had been working or cleared to land. My developmental said something and that is when the Local 2 controller realized that it was his airplane that landed on our runway.In my opinion this situation should have never happened. I should have trusted my instinct to realize that something was not right and immediately visually correlated our planes out the window and on the radar. The developmental should have known through his scan that there was an additional airplane for his runway and spoke up. The Local 2 controller should have indicated at some point that he had an aircraft unaccounted for and that may have been the clue to indicate to us that we had an unauthorized plane landing our runway. I can't remember the circumstances; but a standalone CIC (who usually also works as a cab coordinator) could have helped to recognize that aircraft lining up for the wrong runway. The pilot also made a great error in not correlating the runway he was landing on to the one he was assigned. Ultimately we were lucky that there was no traffic in confliction with Aircraft X and he landed safely and without further incident. I think that a Lessons Learned discussion with the workforce would help prevent further occurrences like this.


Synopsis: A single engine Cessna pilot is cleared to land on Runway 3L at PRC; however pilot lands on Runway 3R instead. He doesn't realize his mistake until after a discussion with the Controller on duty after parking the airplane.