B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Confusion; Distraction; Situational Awareness
Conflict NMAC; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action; Flight Crew Returned To Clearance
Procedure; Aircraft; Airspace Structure
TCAS Climb Alert complied with during approach to 16L at SEA. Conflict was VFR traffic at BFI. I called SEATAC tower after landing and he said this has happened several times in the past. He said there is a small area of overlap in the airspace used by SEA and BFI traffic.
An air carrier on approach to SEA had a near miss with an aircraft in the BFI pattern while both aircraft were transiting a small area of airport airspace overlap.