Small Aircraft
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1.7
Situational Awareness; Confusion; Training / Qualification; Communication Breakdown
ATC Issue All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure; Airspace Structure
Aircraft X departed ZZZ on an IFR flight plan. I was conducting training at the time and was sitting at the adjacent scope. On initial contact the trainee climbed the aircraft to 3;000 feet. A few minutes later my trainee goes to terminate radar services and the pilot said he's IFR wanting practice approaches. I immediately took over and vectored the aircraft away from the Minimum Vectoring Altitude and climbed them to 3;500 feet. The aircraft entered the Minimum Vectoring Altitude MVA below the minimum altitude.
At approximately XA10z Aircraft X departed ZZZ airport Runway XX left assigned heading 160 IFR. I on initial contact gave Aircraft X a VFR climb to at or below 3000 which he read back and complied with. Approximately two minutes later I gave Aircraft X instructions to turn on course ZZZ1 airport. Both instructions mistakenly VFR instructions; which Aircraft X complied with. Approximately XA15 I terminated Aircraft X; instructed to squawk 1200 and change to advisory frequency approved. Aircraft X responded with 'I just want to make sure we get the right IFR cancellation for our flight plan' at that time I realized that they were not; in fact VFR; but an IFR aircraft. My trainer immediately took action to turn Aircraft X away from the antenna. Which they were within the 3300 ft MVA of at 3000 ft. Aircraft X immediately reported the antenna in sight and was given a turn for their IFR approach to Runway X at ZZZ1 airport. The weather was VFR. The antenna is 2348 feet tall. A better scan on my part. The IFR flight plan was sitting in front of me; also he showed IFR in the radar data block.
TRACON Instructor and their developmental reported they allowed an IFR aircraft to fly below the Minimum Vectoring Altitude because they thought the aircraft was on a VFR flight plan.