What happened
While traveling from Evans Head, New South Wales, to Boonah, Queensland, the pilot of a Wittman Tailwind, registration VH-TWQ, diverted to Casino due to low cloud cover over the McPherson Range. After a fifty-minute delay on the ground, the pilot departed Casino, attempting a new route to reach the destination. During the flight, the aircraft entered an area where visibility was significantly reduced. Approximately fifteen minutes after takeoff, the aircraft performed a series of rapid climbs and descents, followed by a descending left turn that resulted in a collision with terrain.
The investigation
The investigation focused on why a pilot operating under visual flight rules (VFR) entered an area of low visibility and subsequently lost control. Examination of the wreckage and the site revealed no mechanical defects or anomalies that contributed to the accident. Furthermore, there was no evidence to suggest the pilot had become incapacitated.
Investigators analyzed the weather forecasts and the pilot's decision-making process. While the graphical area forecasts did not strictly prohibit VFR flight, they did indicate the potential for cloud, rain, and dust that could drop visibility below VFR requirements. The pilot had previously demonstrated an awareness of weather risks by diverting to Casino, but the decision to depart Casino likely relied on the hope that conditions further inland would remain acceptable. The investigation noted that the pilot's climb to 4,100 ft likely took the aircraft above the observed cloud base of 2,600–2,800 ft, but subsequent maneuvers and entering cloud near the Tooloom Fire Tower led to the loss of visual reference.
Findings
- The pilot's decision to depart Casino was likely based on the assumption that weather conditions over the ranges would permit VFR flight.
- The aircraft entered an area of deteriorating visibility, which may have prompted the rapid changes in altitude and groundspeed.
- The pilot likely entered cloud during a climb near the Tooloom Fire Tower, leading to the loss of visual contact with the terrain.