Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 4.5
Distraction; Situational Awareness; Training / Qualification
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Provided Assistance; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Took Evasive Action
Human Factors; Airspace Structure
I was giving training at R-41. Sector 40 was open. We were working approximately 4 OAK arrivals that were descending via the WINDSR (OPD) arrival. I was looking up the arrival chart to discuss published speeds; phraseology options and techniques for assigning speeds. As I was discussing this with the developmental; Aircraft X reported that they were responding to an RA. We then saw the VFR traffic and acknowledged the RA and issued the traffic advisory. The developmental advised the conflict alert had previously gone off but he evaluated and suppressed it. At the time the 1200 code was at approximately 7;000 feet and the Aircraft X was descending from 21000 feet on the WNDSR arrival. When Aircraft X responded to the RA their altitude was approximately 16;000 feet and the VFR target was approximately 15;000 feet descending.TCAS RA's happen daily at sectors 40/41. There is a high volume of VFR sightseeing traffic; VFR flight training; skydiving aircraft; and many uncontrolled airports. I had an RA last year because I was busy issuing traffic advisories to a VFR aircraft in conflict with an OAK arrival. During this time a 1200 code departed DVO and climbed into a jet at 5000 feet between SGD and STS. My recommendation at that time was to create an Alert Area for the Sonoma valley. Alert Areas are clearly depicted on sectional charts and as a pilot and flight instructor I would definitely avoid flying through one; especially if I was not talking to ATC. The 1200 code in this event was a [business jet]. I would assume a business jet pilot would also avoid flying through an Alert Area VFR without at least getting flight following. If we could remove a fraction of VFR traffic from that area it would increase safety. At the very least it would encourage VFR traffic to call for flight following.My recommendation remains the same. To help prevent safety issues like this from reoccurring create an Alert Area over Sonoma Valley. An area that encompasses the airspace south from STS to CA35; west to PYE; and east to APC.
ZOA Controller reported an air carrier on arrival responded to an RA of a VFR target not in communication with ATC. The Center Controller did not notice that the VFR target was a factor for the arrival.