Small Aircraft
Air Traffic Control Developmental
Situational Awareness; Distraction; Training / Qualification; Workload
ATC Issue All Types; Airspace Violation All Types; Conflict NMAC
Flight Crew Took Evasive Action
Airspace Structure; Human Factors; Procedure
I started briefing for Local East/West position. I was told about Aircraft X on a south departure. I took the position. Aircraft Y appeared southbound off a satellite airport climbing. I had to re-verify an arrival's landing clearance due to miscommunication of strip-marking. The event occurred with Aircraft X descending to avoid. Aircraft X called stating an aircraft was above them and they had to dive to avoid them. Upon review of the event the conflicting aircraft was Aircraft Y turning towards SEA for transition. No point out was given. I will continue to work on my scan and remain constantly vigilant about my VFR departures in the case of abnormal situations.
BFI Tower Controller reported a VFR departure reported a near miss with traffic that had not been pointed out to the Controller.