B737 Undifferentiated or Other Model
Air Traffic Control Developmental
Distraction; Fatigue; Situational Awareness
ATC Issue All Types; Conflict Airborne Conflict
Air Traffic Control Issued New Clearance
Human Factors
A Super King Air 350 was orbiting over [a nearby lake] at 12;500 and had been there for approximately 1 hour. With previous ZZZ departures; I had utilized vectors to avoid the Super King Air's flight path and keep departure traffic climbing. I had just finished resolving a conflict involving merging target procedures and coordination with multiple sectors. When a 737-700 checked on they were direct OAL; I instructed them to climb and maintain 16;000. My relief showed up at the position and I began the relief brief. I immediately went into the checklist and started the brief. During the brief I noticed the Super King Air was going to be a conflict with the B737-700 and I instructed the B737-700 to 'turn 10 degrees to the left vector for traffic' I did not call traffic with the vector. This vector put the B737-700 in a worse position to avoid the Super King Air's flight path. I continued on with the relief brief; and a few seconds later the relieving Controller advised me that I needed to turn the B737-700 more to avoid the Super King Air. I then instructed the B737-700 to 'turn 20 degrees to the left.' The B737-700 responded to my instructions; after they responded I realized that the control instructions I provided would not solve the conflict. I then attempted to turn the Super King Air with no acknowledgment. As the B737-700 was climbing through 11;100 I instructed them to amend altitude and maintain 12;000 and issued traffic. I received no immediate reply from the B737-700; a few seconds later they informed me that they were stopping at 12;000 for a TCAS RA. The Super King Air was never issued traffic on the B737-700. Recommendation; I had worked several busy sessions this day and was experiencing some mental fatigue. When my relief arrived I started the brief to soon. In the future; prior to starting the briefing I will take more time to review my traffic to ensure I have correctly resolved any potential conflicts. I told the B737-700 vectors to the left when I was thinking right turns; and continued to make the problem worse by issuing another left turn instead of a right turn. I think this was in part to being mentally fatigued. I will continue to improve my hearback/readback skills to avoid these mistakes. I will also issue traffic with the vector. If I had done that then maybe the B737-700 would have questioned the direction of the turn. Anticipating where VFR aircraft in and orbit will be and trying to vector around them is a bad practice. Going forward I will use altitude separation first as a 'paper stop' then apply vectors if necessary to remove the 'paper stop.'
TRACON Controller described a TCAS RA event when failing to note a developing conflict during a relief briefing; the reporter acknowledged altitude separation should have been used in this scenario.