Beechjet 400
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 5.0
Confusion; Distraction; Situational Awareness; Workload
ATC Issue All Types; Airspace Violation All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance
Company Policy; Human Factors
After having a long period of time off I came back and worked 2 days before this. Summer traffic is known to be busy. We had 2 call-ins and there wasn't anyone to come help me. I was working 3 sectors combined and lost the picture. It was noticed 2 hours earlier in the day by the CIC (Controller In Charge) that we would be short around this time; which we only had CIC that day; and we should call in overtime. No one was called; the [Operations Manager] didn't approve it. The multiple sectors and frequencies were overwhelming. I didn't have a D-Side (Assist) and had to give a clearance to Flight Data that is new to giving clearances. I gave them the clearance and then had to repeat myself; meanwhile; getting behind on frequency with multiple aircraft calling. I turned a departure on course and he sped up more than I thought while the aircraft I stopped below shallowed out his climb. I missed it. Oakland High called and got control and fixed my situation. I think I missed a point out to Oakland Low on the slow climber too; I really don't know. I was distracted by a primary target going straight towards a regional jet on approach that took all the attention. I finally was able to split a sector to another controller. I wasn't able to give a real briefing or hand off data blocks. He had to okay them. It was an unsafe situation. When I sat down I said; 'This is too much for one person' then it took what felt like forever for someone to split the sector and help.
ZSE Controller working combined sectors reported a loss of separation and an airspace violation due to lack of staffing.