Small Aircraft; Low Wing; 2 Eng; Retractable Gear
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 26
Training / Qualification; Situational Awareness; Human-Machine Interface; Distraction; Confusion; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach
Human Factors; ATC Equipment / Nav Facility / Buildings; Procedure
While giving OJT on Local Control; we experienced an ARTS malfunction.  We had primary and secondary radar but not associated ARTS tags.  Radar handed off Aircraft X; on a visual approach to Runway 13 following Aircraft Z.   Shortly after Radar handed off Aircraft Y; following Aircraft X on a visual approach.  Aircraft X advised that he needed a 360 because he was too high.  While I was explaining that due to traffic following we could not issue the 360 to the pilot; the Developmental approved the request but went back and told the pilot of Aircraft X correction.  I told the pilot to fly runway heading and climb to 3;000 which is the standard missed approach/go around procedure at BTR.  The pilot of Aircraft X continued in a climbing right turn instead of runway heading of 130.  Aircraft Y had a TCAS RA and turned and climbed to avoid the traffic.  The Developmental saw the conflict visually and started issuing traffic to both aircraft.
At approximately XA:49 all the ARTS data blocks froze on the radar.  At the time I had at least 5 aircraft that I was working into the airport.  The aircraft that was number one; Aircraft Y; was on about a 6 mile final and I cleared him for a visual approach and switched him to the tower.  Aircraft X was about 8 NW of the airport when I cleared him to follow the first Aircraft Y; which he had in sight; and switched him to the tower.  Aircraft Y was on the left downwind for 13 about 7 NE of the airport when I pointed Aircraft X out to him.  He said he had him in sight and I cleared him to follow the Aircraft X on the visual approach.  Aircraft Y called me later saying that he was climbing in response to an RA.  Apparently at some point Aircraft X decided to make a 360 on final after I had switched him to the tower.  I did not have any ARTS during this event only primary radar. The ARTS came back at approximately [5 minutes later] as Aircraft Y was climbing out on final.  Aircraft X was maneuvering behind and below him on final.  If Aircraft X had not made a 360 Aircraft Y would have been well behind him. Probably 3 to 4 miles.  Training was also occurring on Local at the time of this event.Don't let pilots make a 360 when traffic is following them.
BTR Controllers report of an aircraft being too high for the approach. The pilot requested a 360 turn to get lower. This was approved by Developmental; then corrected by him to fly runway heading. The aircraft making missed approach now becomes a conflict with another aircraft. Controllers' report of having an ARTS failure during this operation.