PA-28R Cherokee Arrow All Series
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 8.0
Time Pressure; Situational Awareness
ATC Issue All Types; Conflict NMAC
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance
Airspace Structure; Human Factors; Procedure
Aircraft X checked in 8 south and was instructed to make left traffic RWY 22L. Aircraft Y was departure roll for a south bound departure. As Aircraft Y started his southbound turn I recognized his course converging with Aircraft X. I issued traffic when they were over a mile apart. Aircraft X reported Aircraft Y in sight below him when they were about 3/4 of a mile apart. It appeared that Aircraft X passed approximately 400 ft above Aircraft Y. I found out today that Aircraft Y reported a NMAC regarding this incident.I should have recognized the conflict sooner and issued instructions like have Aircraft Y fly straight out till he was passed Aircraft X.
FFZ Tower Controller reported overlooking a potential conflict between an arriving and departing aircraft until they were almost converging.