Narrative:

Four arrivals were being sequenced. The first arrival was being vectored to one runway while aircraft X was told to expect an intersecting runway. The first arrival; aircraft Y; reported the field in sight 10 miles north of the airport. Aircraft Y was instructed to conduct a base turn within the final approach fix; which he said he would. Once cleared for the approach; aircraft Y turned away from the airport into the left downwind which caused a problem from aircraft X landing on the intersecting runway. Meanwhile aircraft Z was coming in from the northwest. Aircraft Z requested turns to the right because of build ups; which affected my plan to put him in the downwind. Aircraft Z was descended to 3000 ft. Once the aircraft X and aircraft Y sequence was not going to work; I put aircraft X on a heading to follow aircraft Y to the same runway and descended them to 2000 ft to have IFR separation from aircraft Z who was direct the airport 12 miles to the west at 3000 ft. My plan was to have aircraft X get aircraft Y in sight and follow him and put aircraft Z behind him. The aircraft X did not get aircraft Y in sight in time and was put on a vector to get across the 11 final approach course to allow aircraft Z to be number 2 to the field. The aircraft flew into a 2200 ft minimum vectoring altitude (MVA) area; when originally he was descended in an 1800 ft MVA area. Once aircraft Z passed aircraft X and landed; aircraft X reported field in sight and landed without further occurrence. My recommendations would be not to descend the aircraft to the lowest altitude. Always allow room to meet the MVA; while also allowing for IFR separation between other aircraft.

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Original NASA ASRS Text

Title: CAE TRACON Controller reported they vectored an aircraft below the Minimum Vectoring Altitude after it unexpectedly initiated a turn off the final approach course which placed them in to conflict with other inbound traffic.

Narrative: Four arrivals were being sequenced. The first arrival was being vectored to one runway while Aircraft X was told to expect an intersecting runway. The first arrival; Aircraft Y; reported the field in sight 10 miles north of the airport. Aircraft Y was instructed to conduct a base turn within the Final Approach Fix; which he said he would. Once cleared for the approach; Aircraft Y turned away from the airport into the left downwind which caused a problem from Aircraft X landing on the intersecting runway. Meanwhile Aircraft Z was coming in from the northwest. Aircraft Z requested turns to the right because of build ups; which affected my plan to put him in the downwind. Aircraft Z was descended to 3000 ft. Once the Aircraft X and Aircraft Y sequence was not going to work; I put Aircraft X on a heading to follow Aircraft Y to the same runway and descended them to 2000 ft to have IFR separation from Aircraft Z who was direct the airport 12 miles to the west at 3000 ft. My plan was to have Aircraft X get Aircraft Y in sight and follow him and put Aircraft Z behind him. The Aircraft X did not get Aircraft Y in sight in time and was put on a vector to get across the 11 final approach course to allow Aircraft Z to be number 2 to the field. The aircraft flew into a 2200 ft Minimum Vectoring Altitude (MVA) area; when originally he was descended in an 1800 ft MVA area. Once Aircraft Z passed Aircraft X and landed; Aircraft X reported field in sight and landed without further occurrence. My recommendations would be not to descend the aircraft to the lowest altitude. Always allow room to meet the MVA; while also allowing for IFR separation between other aircraft.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.