Citationjet (C525/C526) - CJ I / II / III / IV
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 4
Confusion; Communication Breakdown
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; Airspace Structure; Human Factors; Airport
[I was] working Aircraft X into EDC. I cleared them for the approach via CUSAT at 4000 ft. They turned early towards the airport. I saw this; told them they were off the approach [and] to cancel approach clearance fly heading 230 and maintain 2500 ft. They continued to send to 1700 ft.; a low altitude alert [was issued and] they declared they were on the visual with the airport. I cleared him for the visual approach. I believe that I could have tried to issue the low altitude warning a little earlier or the pilot could have said he had the field insight as soon as I told him [to] cancel the approach.
A TRACON Controller reported an aircraft cleared for an approach turned toward the airport early and descended below the minimum safe terrain avoidance altitude.