T6A Texan II / Harvard II (Raytheon)
Air Traffic Control Fully Certified
Communication Breakdown; Distraction
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Separated Traffic
Human Factors
I was working the DR1 position and providing Aircraft vectors to the ILS Runway 17L. Aircraft was assigned 3;000 feet to maintain. I had given Aircraft a 140 turn to join the localizer and went on to other traffic. I went back to Aircraft and cleared for the ILS. Just after I finished issuing the instructions I noticed Aircraft had already descended through 2;800 feet in the vicinity of antennas requiring a 3;000 feet MVA. The pilot read back 3;000 feet correctly yet was still below 3;000 feet. Thinking I just busted the MVA I notified the CIC; who immediately started reviewing tapes and falcon. Aircraft was already clear of the obstacle so I allowed them to continue on the approach as they were in a critical phase of flight to climb up to come right back down. Review of the tapes and falcon showed a pilot deviation as he never went back to 3;000 feet. I could've cancelled the approach clearance and re-vectored for the approach or reiterated the pilot maintain 3;000 feet.
SDF Controller reported a TEX2 descended below assigned altitude entering a higher MVA.