Small Transport; Low Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 25
Situational Awareness
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Human Factors; Aircraft; Procedure
Aircraft X was cleared for GPS RWY 31 approach. On about an 8 mile final (3 miles before the FAF); the low altitude alarm went off. I noticed the aircraft at 800 ft. The crossing restriction at the FAF is 1500 FT. The aircraft was talking to tower. I alerted the tower controller; who then alerted the pilot. The pilot stated that 'He was descending to his minimum descent altitude' then subsequently saw the airport. The field was VFR at the time with OVC012.I don't really know what happened; but pilots must be diligent to where/when they can begin descent.
ACY TRACON Controller describes an aircraft that descends below the FAF altitude to the minimum descent altitude causing a low altitude alert. The aircraft is advised of the low altitude and then sees the airport and lands safely.