Date: 202102
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Operator: FBO
Operating under: Part 91
Mission: Training
Flight phase: Other VFR Traffic Pattern
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Second aircraft: Any Unknown or Unlisted Aircraft Manufacturer
Reporter organization: Government
Reporter function: Local; Instructor
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Training / Qualification; Communication Breakdown; Confusion; Situational Awareness
Second reporter function: Local; Trainee
Anomaly: ATC Issue All Types; Conflict NMAC; Deviation - Track / Heading All Types; Inflight Event / Encounter Aircraft
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Took Evasive Action
Contributing factors: Airport; Procedure
Primary problem: Procedure

Narrative: Training was in progress on Local control. Aircraft X was sequenced to follow Aircraft Y. Aircraft X had the wrong aircraft in sight and turned base early and at the same time as Aircraft Y. Aircraft Y had to maneuver off final to the north for spacing. Aircraft Y called the tower and spoke with me; the CIC (Controller in Charge); and said Aircraft X got as close as 50 ft. prior to him maneuvering. Aircraft X was also on his check ride.


Second narrative: I was training on the Local Control position. There were 4 VFR aircraft in the traffic pattern for RWY XX and 1 VFR aircraft on practice approach RWY YY. Aircraft Y was VFR in left traffic for RWY XX and given a sequence to follow Aircraft X. Aircraft X was VFR in right traffic for RWY XX. Aircraft Y was given a sequence of number 4; to follow Aircraft X on right downwind. Aircraft Y was extending their downwind until they had their traffic in sight. Aircraft Y asked if their traffic was turning final RWY XX. I visually scanned the traffic pattern to verify Aircraft X position. I saw Aircraft X on final for RWY XX. Aircraft X was the 3rd aircraft on final at the time and was on an approximately 4NM final. I cleared Aircraft Y to land RWY XX after my visual scan. Aircraft Y must have had the incorrect aircraft in sight; the aircraft preceding Aircraft X was an Piper. Aircraft Y flew into the flight path of Aircraft X; cutting them off. Aircraft Y had to make a quick turn north bound to avoid Aircraft X. Aircraft X saw Aircraft Y; after Aircraft Y turned to the north; and Aircraft X made a south turn to avoid Aircraft Y. At this time Aircraft X made a call to Local Control that he was making his north turn to avoid Aircraft Y. I did not see the two aircraft turning to avoid until Aircraft X made his call for the north turn. Aircraft Y rejoined the RWY XX final; in front of Aircraft Y; and was reissued a landing clearance for RWY XX. Aircraft Y was instructed to make a 270 degree turn back to final and rejoined RWY XX final behind Aircraft X. Aircraft X was reissued a landing clearance for RWY XX. Both aircraft landed without further incident. About 10 minutes after Aircraft X landed; the pilot called the tower to let us know that Aircraft Y was within close proximity to him and he would be filing a safety report.


Synopsis: ATC Instructor and trainee reported misidentified aircraft in traffic pattern resulted in NMAC.