Regional Jet 700 ER/LR (CRJ700)
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 12
Situational Awareness; Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Airspace Structure; Human Factors; Procedure
I was vectoring an aircraft on a 6 mile right base. I descended the aircraft to the Minimum Vectoring Altitude (MVA) of 3;500 feet. The Low Altitude alert went off as the aircraft was past the obstacle descending through 2;700 feet. After reviewing data I missed the read back. Aircraft X read back 2;500 not 3;500. The aircraft crossed the obstacle at 3;000 feet; five hundred feet below the MVA. I should not have used an altitude such as three thousand five hundred that can easily sound like two thousand five hundred. I should vector to avoid overflight of antennas and be more proactive on read backs.
MSN TRACON Controller reported not detecting an aircraft read back the wrong altitude and it descended below the Minimum Vectoring Altitude.