A319
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 5.8
Situational Awareness
ATC Issue All Types; Aircraft Equipment Problem Less Severe; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Aircraft; Human Factors
We were training combined with dual ILS approaches with monitors. Runway 36L was being inspected so we were using Runway 35C and Runway 35L. Aircraft X checked on and had reported avionics issues and wanted a long final and notified us that if the aircraft didn't capture they would need to go around. Because of this I instructed the trainee to descend Aircraft X to 3;000 feet. At the time I did not realize the 3;500 feet MVA was on the final on the projected flight path but I wanted Aircraft X to be at a lower altitude in case they did not capture the localizer and went through as there was going to be an aircraft on the parallel final. By having those at a lower altitude there would be more time to turn Aircraft X away from the higher descending aircraft on Runway 35R. Aircraft X did go through the localizer and we turned them to rejoin. We did realize Aircraft X was going to enter the MVA prior to entering the MVA however with the possible complexities of the avionics issue I chose to not climb the aircraft to 3;500 feet to avoid it as it's flight path was going to be north of the antennas and would be 500 feet above any obstacle. I decided this would be a safer operation than adding a climb to an aircraft with avionics issues. I would've stayed at 3;500 feet instead of 3;000 feet.
D10 TRACON instructor advised trainee to descend an aircraft below the MVA.