EMB ERJ 170/175 ER/LR
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 5
Distraction; Communication Breakdown; Training / Qualification
ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance
Procedure; Human Factors
One runway operation due to construction. Training new controller on north radar combined up with south radar. We were talking about sequencing and spacing for general aviation aircraft following a B737 from the south. Aircraft X was put on a vector heading 260 to maintain 9000 for spacing with the multiple GA aircraft inbound from the north. Aircraft X read back 260 down to 6000 and both trainee and I missed the read back. We then went back to talking about the spacing needed for the previous arrivals. We both noticed the altitude when he was descending through 6500 in a 6500 MVA and told him to climb. I totally missed the read back.Don't assume the pilots are going to read the headings and altitudes back correctly. I think the 260 heading kind of jostled the pilots mind so that is where he got 6000 for his final altitude he read back to us. Complacency is not a good attribute in this career. No harm happened thankfully but it was a wakeup call for me to be more vigilant in getting correct read backs.
BOI TRACON Controller reported a missed read back which almost led to an aircraft descending below the Minimum Vectoring Altitude.