The pilot of a Piper PA‑34 aircraft, registered VH-FEJ (FEJ), submitted a flight plan from Archerfield to Cairns via Townsville, Queensland. Prior to departure, air traffic control (ATC) at Archerfield updated the flight plan from visual flight rules (VFR) to instrument flight rules (IFR) at the pilot’s request.
The updated flight plan was transmitted via a change message to the various ATC agencies responsible for the aircraft. Townsville ATC, operated by the Department of Defence, utilised computer printed flight progress strips (strips) and the strip for FEJ was printed prior to the change message being processed, indicating that FEJ was a VFR flight.
When the pilot of FEJ contacted Townsville Approach, he requested a runway 01 instrument landing system approach. The Approach controller cleared the aircraft to track direct to the initial approach fix and, once the aircraft was within 36 NM, cleared the pilot of FEJ to descend to 4,000 ft.
Shortly after, the Approach controller became concerned about FEJ maintaining visual meteorological conditions given the weather in the area, and queried the pilot on the aircraft’s flight category. On being advised that FEJ was an IFR flight and in cloud, the Approach controller immediately instructed the pilot to stop the descent at 5,500 ft. By the time the pilot was able to arrest the aircraft’s descent, FEJ had reached 5,200 ft. Though FEJ did not descend below the lowest safe altitude on the aircraft’s track, terrain clearance on track was not assured until FEJ climbed back to 5,500 ft. Shortly after, the pilot became visual and FEJ landed without further incident.
As a result of this occurrence, the Department of Defence has advised the ATSB that controllers are now required to check flight progress strips thoroughly prior to passing them to Approach, ensuring that the data was correct.