Medium Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1
Situational Awareness
ATC Issue All Types; Conflict NMAC
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance
Airport; Airspace Structure; Human Factors; Procedure
I was working Local and CIC position. I got a call on the shout line from NUQ Tower asking me if I had their traffic in sight; Aircraft X. I looked out the window because it had a Low Altitude alert and saw the aircraft when they were around PUDBY intersection and I told them I had them in sight. Aircraft X was landing/dep. 14 at NUQ and we were landing/dep. 13 and we are 5 miles apart. At the time I had an Aircraft Z and Aircraft Y in traffic pattern; the Aircraft Z was doing a touch and go; and soon after I cleared the Aircraft Y I kept Aircraft X insight outside the window but did not correlate the altitude with the radar. I noticed the Aircraft X has not started their turn to base; while my Aircraft Y was on the departure end so I told the Aircraft Y to start his crosswind turn and stop his climb. Once the Aircraft X started his base turn 1/2 mile in my upwind; NUQ did say he had my Aircraft Y insight. Aircraft X had Aircraft Y in sight but I did not give traffic to the Aircraft Y; which I believe played a crucial part in this. The Aircraft X overflew the Aircraft Y when they were turning downwind. The Aircraft Y was at 600 ft and Aircraft X 800 ft. I recommend that aircraft that are circling west of NUQ landing 14 during VFR conditions should cross PAO field above 1300 for local PAO traffic.
PAO Tower Controller reported a NMAC between an aircraft in their pattern and an aircraft deviating from the adjacent airports final approach course.