A nct controller had to cancel an aircraft's approach clearance and vector it around VFR traffic on ...

Narrative:

I was working the arrival sector for the airport. Many VFR aircraft fly near the airport without contacting ATC and at altitudes that get in the way of many of the arrivals. I was working aircraft X inbound. I cleared him for the ILS via the RNAV arrival. I cancelled his approach clearance because there was a VFR aircraft in his path at 4500 feet and climbing. I turned aircraft X to a 300 degree heading and then had to turn him again to a 360 degree heading to avoid the traffic. I put aircraft X direct to the airport and eventually cleared him for the visual approach. Aircraft Y was about 6-10 miles behind aircraft X on the RNAV arrival. Initially I didn't clear him for the approach but then did when I thought there were not going to be any more VFR aircraft in his way. When I finished with aircraft X; a helicopter that was doing air work 5 miles west of the airport told me he was ready to return to the airport. As I updated the data blocks to reflect that; aircraft Y said he has someone on his TCAS. When I looked at him there was another southbound VFR aircraft that was at 4500 feet and climbing; the same altitude as aircraft Y and 1 mile away. I issued aircraft Y a traffic alert and told him to climb to 5000 feet. He didn't say he responded to a TCAS by when I reviewed the data it showed that he climbed higher than 5000 feet. I asked him to report the airport in sight and then cleared him for the visual approach. I didn't see the second VFR aircraft. That area is always congested with VFR aircraft that don't talk to anyone. They are at altitudes that put them in close proximity of commercial aircraft. Everyone I ask about putting a class C airspace in that area has said that there's nothing that can be done. There must be something done to prevent an accident from occurring. If there was a 10 mile ring around the IAF that requires all aircraft to talk to ATC; things would be better because I would know exactly what the aircraft's intentions are and I could control them accordingly. That area around the IAF must be sterilized to prevent something catastrophic from happening. We have to be proactive and do something before it's too late. Controllers are humans; we can't see everything.

Original NASA ASRS Text

Title: A NCT Controller had to cancel an aircraft's approach clearance and vector it around VFR traffic on the final approach course. The aircraft following this aircraft responded to a RA for VFR traffic on the final approach course. The VFR aircraft were not in communication with ATC.

Narrative: I was working the arrival sector for the airport. Many VFR aircraft fly near the airport without contacting ATC and at altitudes that get in the way of many of the arrivals. I was working Aircraft X inbound. I cleared him for the ILS via the RNAV arrival. I cancelled his approach clearance because there was a VFR aircraft in his path at 4500 feet and climbing. I turned Aircraft X to a 300 degree heading and then had to turn him again to a 360 degree heading to avoid the traffic. I put Aircraft X direct to the airport and eventually cleared him for the Visual Approach. Aircraft Y was about 6-10 miles behind Aircraft X on the RNAV arrival. Initially I didn't clear him for the approach but then did when I thought there were not going to be any more VFR aircraft in his way. When I finished with Aircraft X; a helicopter that was doing air work 5 miles west of the airport told me he was ready to return to the airport. As I updated the data blocks to reflect that; Aircraft Y said he has someone on his TCAS. When I looked at him there was another southbound VFR aircraft that was at 4500 feet and climbing; the same altitude as Aircraft Y and 1 mile away. I issued Aircraft Y a traffic alert and told him to climb to 5000 feet. He didn't say he responded to a TCAS by when I reviewed the data it showed that he climbed higher than 5000 feet. I asked him to report the airport in sight and then cleared him for the Visual Approach. I didn't see the second VFR aircraft. That area is always congested with VFR aircraft that don't talk to anyone. They are at altitudes that put them in close proximity of commercial aircraft. Everyone I ask about putting a Class C airspace in that area has said that there's nothing that can be done. There must be something done to prevent an accident from occurring. If there was a 10 mile ring around the IAF that requires all aircraft to talk to ATC; things would be better because I would know exactly what the aircraft's intentions are and I could control them accordingly. That area around the IAF must be sterilized to prevent something catastrophic from happening. We have to be proactive and do something before it's too late. Controllers are humans; we can't see everything.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1335040
Time
Date	201602
Local Time Of Day	1801-2400
Place
Locale Reference	NCT.TRACON
State Reference	CA
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	Other Instrument Approach STAR SILCN3
Flight Plan	IFR
Aircraft 2
Make Model Name	Medium Large Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	None STAR SILCN3
Flight Plan	IFR
Person 1
Function	Approach
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (yrs) 0.5
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict

A nct controller had to cancel an aircraft's approach clearance and vector it around VFR traffic on the final approach course. The aircraft following this aircraft responded to a RA for VFR traffic on the final approach course. The VFR aircraft were not in communication with ATC.