Air Traffic Control Fully Certified
Situational Awareness; Confusion
ATC Issue All Types
Air Traffic Control Issued New Clearance
Human Factors
On short final a B737 requested a 360 and did not give a reason why; traffic was relevantly slow and I had one A319 six mile final cleared to land and looking on my scope I saw a second B737 flight inbound Runway 25L approach talking to Approach about 17 mile final. I told the second B737 to fly runway heading and I would coordinate and see if I could get him a closed traffic pattern. I coordinated to Final Sector to see if they would allow a closed traffic behind the A319. Hesitantly; the Final Sector approved the request; I believe that is what pushed me to opt for the closed traffic. As the second B737 climbed; I issued left closed traffic; adding I need you to keep it tight for traffic on 15 mile final; and instructed to advise the A319 on 2 mile final in sight. The second B737 reported the A319 in sight and I instructed the second B737 to follow the A319; 'cleared visual Runway 25L' and then also told the second B737 traffic 15 mile final. The second B737 did not turn base to final and was nearly abeam the company aircraft. I asked if I could take the first B737 to the 19's and he said that was fine. I told the second B737 to fly north for Runway 19L; as I instructed this; I noticed Final had started turning another B737 and another A319 north to the 19's to avoid the first B737. I had not had time to coordinate my intentions at this point to Final sector to avoid them changing the second B737 and second A319's route to the 19's. I observed the first B737 turn north and ask the B737 if he still had his company in sight; he reported the company insight. I told him to follow his company to the 19L and maintain visual separation. Tower had visual out the window with all aircraft at all times. I do not believe there was loss of separation or a vector below the MVA. I am fairly low in experience and during training our Tower simulator was not running yet; I have requested to have a few days working on the simulator running problems that involve unusual situations. I need to continue to improve my skills and make better decisions during times of unusual situations and will continue to strive to be better.
Limited experienced Controller described a complex traffic event that eventually resulted in a go around; the reporter indicated the need for training on unusual traffic situations.