Date: 201705
Local time of day: 1801-2400
Location: ZOA.ARTCC, CA
Aircraft: Light Transport; Low Wing; 2 Turboprop Eng
Operator: Personal
Operating under: Part 91
Mission: Test Flight / Demonstration
Flight phase: Cruise
Airspace: Class A ZOA
ATC / advisory: Center ZOA
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Time Pressure; Workload
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance
Contributing factors: Staffing; Company Policy
Primary problem: Staffing

Narrative: Sector 11 was overrun with traffic. The volume and complexity were high. I was working sector 11 combined. Sector 11 is responsible for departures southeast bound from the major airports SFO; OAK and SJC and numerous other airports located in NorCal Approaches airspace; and the main southeastern arrival route into OAK. During the time of the incident there was Aircraft X at 21000 feet conducting an operation in the northern part of Sector 11 which required it to maneuver in the area where some of the departures from and arrivals into NorCal Approach's airspace needed to climb or descend through its altitude.Its location added to the complexity because several departures needed to be held below; expedited above or vectored around it. There are several non-turbojet aircraft preferred routings through Sector 11's airspace that put them in direct conflict with the jet arrival and departure traffic. The majority of the time the Sector 11 controller issues props a routing around the jets once they're on frequency. (As you'll see this is a huge problem for this sector) You can see this with the [aircraft] entering Sector 11 from the north and the three non-turbojet aircraft entering Sector 11 from Sector 14. The props entering Sector 11 from Sector 14 were vectored off their preferred route because Sector 14 was busy and needed to vector them off route. This was a huge factor in complicating the backup and overrun in Sector 11. They were in a location where it wasn't safe to climb the departures above them.Therefore; during the busy departure rush numerous departures needed to be held down an issued speed restrictions which contributed to the backup. I requested an Assist earlier when I realized that it was going to get really busy. The Controller in Charge (CIC) said there was no one available; but someone would be back soon. In the meantime the CIC did as much coordination as she could. When the Radar Assist arrived it was too late to 'control' the traffic situation. It was more damage control than air traffic control. Also there are three pairs of transmitter and receiver sites. During the relief briefing I was told one pair was unusable and was turned off. There are three frequency pairs there for a reason. They're used for different areas of the sector. Therefore there were some replies I couldn't hear; yet could see the turned off frequency light up. After I noticed that I turned it back on and it added an almost non understandable quality to the read backs.The controller can't be the only line of defense against high volumes and complex traffic situations which require divided attention. If we continue down this road this is a prescription for disaster and its only a matter of time before the right combination of factors converge to create a dangerous and possible fatal situation. What; if any; other controls are in place to prevent a situation like this from happening? Who else has a role in ensuring the integrity/safety of the sector/system and what did they do in this situation to provide some form of relief? I would route the non-turbojets out of Sector 11's airspace when the traffic volume is projected to be high or other factors warrant it. There should never be a time when help is not available in this job. Whats the worse thing that could happen? There have only been a few times during my career when I knew I was at the limit of my ability and consciously told myself I can only do what I can do. It doesn't matter how often airplanes call me or how often I'm called on the landline. I need to stay focused on this. This was one of those times. CIC's/Supervisors should remain vigilant for situations like these; plan accordingly and be proactive in preventing the development of them.




Synopsis: A Center Controller reported the sector became overloaded with traffic; but no action was taken to reduce the traffic flow into the airspace.