Date: 201811
Local time of day: 0001-0600
Location: PAO.Tower, CA
Aircraft: Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Flight phase: Final Approach
Airspace: Class D PAO
ATC / advisory: Tower PAO
Second aircraft: Military
Reporter organization: Government
Reporter function: Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Distraction; Communication Breakdown
Second reporter function: Approach
Anomaly: ATC Issue All Types; Conflict NMAC
Detector: Person Air Traffic Control; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action
Contributing factors: Airspace Structure; Human Factors; Procedure
Primary problem: Procedure

Narrative: Aircraft X was inbound IFR on the GPS Runway 31 approach. Aircraft Y; a VFR flight of 3 [military aircraft]; was holding over Moffett Field (NUQ) in a left orbit at approximately 1;100 feet waiting for the appropriate time to overfly Levi Stadium. I issued traffic to Aircraft X when the flight of 3 were approximately 3 NM away and he reported the traffic insight. The [flight of 3] turned left directly towards Aircraft X on the approach at a similar altitude. Aircraft X continued his transmission reporting them insight and said he was turning to avoid them as they turned into him around a 3NM final to Runway 31. After he passed the traffic I asked if Aircraft X had the airport in sight; he replied he did. He then mentioned wanting to talk about the jets passing him and I replied that I would give him the tower number to call once he landed. After Aircraft X landed without incident; I gave him the tower number and when he called he wanted to report the NMAC. This was the second NMAC report I had to file with one of my IFR arrivals and Aircraft Y [flight] orbiting over Moffett Field in less than 15 minutes. I had tried earlier to coordinate with Moffett to ensure the [flight of 3] wouldn't be a conflict with Aircraft X inbound and still a situation developed. I was given an impression that Moffett was having some difficulty with holding instructions to flight; but not something I can confirm. Either way; the speed the [flight of 3] were orbiting over NUQ made it very hard for me to miss with my slower traffic. If I had a better idea of what they were doing; I could then issue better advisories to my pilots to avoid the unsafe proximity they got into. On occasion there was military fly over/bys at Levi Stadium. It might help if in the planning phases for these events that a representative from Moffett; San Jose; Palo Alto; NorCal Approach and the flight all have a conference call or in person meeting to discuss the operation so that everyone can get on the same page and avoid anything like this from happening again.


Second narrative: Aircraft Z was on the VOR approach to PAO. While Aircraft Z was on a 3 mile final to PAO at 1;500; [flight of 3 military aircraft] were in the VFR pattern at NUQ at 1;600 over flew Aircraft Z. The weather in the area was smoky and visibility was not good. There was an aircraft operating over the stadium of the departure end of SJC airport dropping streamers and parachute jumpers. It was a lot of coordination and a lot of detail to keep that situation safe and not to delay SJC departures too much. The whole situation had a lot of things line up for something to happen. We hardly ever have [aircraft] holding in the NUQ pattern let alone parachute operation [nearby]. Aircraft hardly ever do the PAO VOR approach. In addition the was a lot of smoke in the area due to the [local] Fire [activity]. Maybe we could have held the [military aircraft] some other place other than over an IFR final approach course.The [military aircraft] were talking with NUQ tower and Aircraft Z was on a different frequency talking to PAO tower.


Synopsis: Controllers and GA pilot reported a NMAC with military aircraft holding for a fly over.