Operational non-compliance involving a Short Bros Pty Ltd SD360-300, VH-MJU, 8km SW Sydney, Aerodrome, NSW on 20 July 1993

The aircraft was 4 miles southwest of Sydney turning right onto heading 160 for left downwind runway 34, and was assigned descent to 4000 feet. Radar information indicated that the aircraft had descended to 3000 feet and this was confirmed by the pilot. The aircraft was recleared to climb immediately to 4000 feet for separation with departing traffic on runway 25. The crew reported that the cockpit workload at the time was high and the pilot not flying missed the "500 feet to go" call. The pilot flying continued the descent to 3000 feet, forgetting that he had been assigned 4000 feet.