What happened
A Cessna 500, registration VH-ANQ, was performing a charter service from Proserpine to Mareeba to transport representatives from five local government authorities to a conference in Airlie Beach. The flight was conducted under Instrument Flight Rules (IFR) with an intended cruising altitude of FL330. After departing Proserpine at 16:35, the aircraft followed its planned route via Townsville.
During the descent phase, the pilot communicated with Cairns Approach, reporting the aircraft's position relative to Biboohra and requesting instructions. Following clearances to descend through various altitudes, the pilot reported at 17:36 that the aircraft was approaching Mareeba visually. After being cleared to circle over the destination due to a delay, the pilot ceased all radio communications following an instruction to descend to 7,000 feet at 17:40.
The wreckage of VH-ANQ was discovered by search helicopters at 02:40 on 12 May 1990. The aircraft had struck the eastern slopes of Mt Emerald, located approximately 15 kilometres south of Mareeba Airport. The initial impact occurred when the left wingtip hit the mountainside while the aircraft was in a wings-level attitude with an eight-degree descent angle. The debris field spread along a track of roughly 350 degrees magnetic.
Findings
Investigators noted a significant discrepancy between the pilot's final radio report and the actual location of the crash. While the last transmission indicated the aircraft was at 10,000 feet and positioned 55 kilometres east of the impact site, the aircraft had actually descended an additional 6,400 feet and drifted far to the west. The specific cause for this unplanned descent and lateral displacement remains undetermined.