Small Aircraft; High Wing; 1 Eng; Fixed Gear
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 3
Distraction; Situational Awareness; Training / Qualification
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic; Flight Crew Executed Go Around / Missed Approach; Flight Crew Requested ATC Assistance / Clarification
Procedure; Human Factors; Airspace Structure; Aircraft
I was the Instructor during the incident. Aircraft X was vectored for an ILS approach. The ceiling was about 900 or 1000 feet overcast. My trainee told the aircraft to intercept the localizer at RESOC at 3500 feet and was cleared for the approach. Aircraft Y was sequenced behind Aircraft X on the localizer. When Aircraft X got to RESOC he turned an unexpected direction as if he was doing some sort of procedure turn. That turn was back up the localizer toward Aircraft Y who was around the same altitude. My trainee started to transmit; when I took over to recover from the imminent loss of separation. Aircraft X was clearly confused and slow to respond if at all. He turned on a heading to diverge as Aircraft Y was climbed to avoid.After separation was reestablished; my first thought was to get Aircraft X which was having difficulty on the ground as soon as possible. The second attempt almost created another loss of separation with traffic on the downwind. Luckily we were ready for that one. We offered Aircraft X an option to fly to an airport where the weather was VFR that was the closest airport where we could legally vector for a Visual Approach. I believe it was the 4th attempt that the aircraft finally made it into the airport; but not without extensive assistance. Another controller was our relief and did a great job of talking to the pilot about required altitudes on final. After coordination; he kept the pilot on the approach control frequency and cleared him to land.I allowed my trainee to take over again; but unfortunately; during the concentration on this particular aircraft; he left Aircraft Y on the downwind at SKF at 2500 feet. The 3000 foot Minimum Vectoring Altitude (MVA) was violated prior to climbing him to the correct altitude. No other incidents occurred. We climbed the aircraft above the layer of clouds and delayed him after his second attempt. Knowing what I know now; I would have delayed him after the first attempt. I should have been more attentive to Aircraft Y to prevent the MVA violation while I was giving specific info to the supervisor.
SAT TRACON Controller; distracted assisting an aircraft having difficulty navigating in inclement weather; allowed an aircraft on downwind vectors to fly below their MVA.