Date: 201704
Local time of day: 0001-0600
Location: FFZ.Airport, AZ
Flight conditions: VMC
Light: Daylight
Aircraft: Small Aircraft
Operator: FBO
Operating under: Part 91
Flight plan: VFR
Mission: Training
Flight phase: Landing; Final Approach
Airspace: Class D FFZ
ATC / advisory: Tower FFZ
Second aircraft: Small Aircraft
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Training / Qualification; Confusion; Situational Awareness
Anomaly: ATC Issue All Types; Conflict NMAC; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Executed Go Around / Missed Approach; Flight Crew Became Reoriented; General Flight Cancelled / Delayed
Contributing factors: Human Factors; Procedure; Aircraft; Airspace Structure
Primary problem: Human Factors

Narrative: Aircraft X had been following Aircraft Y in the traffic pattern. I cleared Aircraft X number 2 to follow Aircraft Y for the touch and go. Aircraft X reported an aircraft off their right and said they were initiating a go around. When I looked back to the final I saw one aircraft lower on final and Aircraft X climbing out higher on the go around. Apparently Aircraft X cut off Aircraft Y which they had been following in the traffic pattern for some time. It did not appear to be any closer than the other 100 plus times [student] pilots had cut each other off in the pattern over the years. Usually I catch these events sooner. I must have been sorting out my upwind traffic. I try to as soon as possible get the departing pattern planes to find and follow the next plane ahead in the pattern so this doesn't happen. I have not had a chance to review the tapes as I was just called at home on my only day off and informed that some sort of NMAC investigation had been started by the FBO which owns both planes involved.Student pilots and instructors could do a better job of finding and following planes. Too many times student pilots are sent out [to] solo way before they are ready to be in a busy; complex traffic pattern. I think there was actually an instructor on Aircraft X; but I am not sure. On the controller side; I would like to work fewer 6 day work weeks. [We are] short staffed and I have more mandatory 6 day weeks than not as of late; and there appears to be no end in sight. Sometimes it could occur and without tracking the planes visually out the window you would not see it coming as the STARS FUSION display is a terrible tool to have work busy VFR traffic at an airport with parallels separated by less than 1;000 feet. The old D-Brite radar display was a far superior tool for the traffic we work. The D-Brite would actually show two targets if two planes departed simultaneously STARS will not. The algorithm that drives the FUSION display is not compatible with our traffic and runway configuration.




Synopsis: FFZ Tower Controller observed an aircraft turn in front of another aircraft which it was supposed to follow.