What happened
During a nighttime transit from the Marshall Islands toward Cairns, Australia, the pilot of the aircraft initiated a descent from FL190 to 12,000 feet specifically to mitigate airframe icing. Following this maneuver, the pilot requested an ascent to FL200. Shortly after beginning the climb, the pilot issued a mayday distress call to Sydney flight service, reporting that the aircraft had entered an uncontrolled descent. No subsequent communications were recorded.
The aircraft is believed to have crashed into the ocean approximately 370 miles east-northeast of Cairns. Despite search efforts, neither the aircraft nor the pilot was located. The flight path involved several previous legs, as the plane was being ferried from Tulsa, Oklahoma. Prior to this leg, a different pilot had aborted a segment of the journey in Oakland due to issues with cabin pressurization. A subsequent pilot landed the aircraft in Oakland while it was overweight, causing structural damage. The final crew member continued the ferry flight via stops in Hawaii and the Marshall Islands.
Findings
Investigations into the disappearance identified several critical environmental and operational factors:
- The flight was operating under thunderstorm and icing conditions.
- The incident occurred during night operations.
- The aircraft was operated with known equipment deficiencies.
- The exact reason for the loss of control remains undetermined.