What happened
At 06:46 local time, a single-engine aircraft departed Lizard Island Airport on a non-scheduled flight bound for Cairns. The flight was carrying the pilot and nine passengers. Shortly after takeoff from runway 1s, the aircraft climbed to 1,750 feet and the pilot engaged the autopilot. While climbing through 3,400 feet, the pilot observed an unusual change in engine noise accompanied by unintended acceleration. Monitoring the Garmin G1000 display, the pilot identified that engine torque and interstage turbine temperature had exceeded redline limits, while fuel flow and gas generator speed readings were non-functional.
In an attempt to manage the situation, the pilot issued a PAN PAN call and began a left turn to return to the departure airfield. Despite efforts to control the climb, the aircraft continued to accelerate, reaching 4,000 feet at 166 knots. The pilot attempted various troubleshooting steps, including manipulating the power, propeller, and emergency power levers, as well as adjusting the fuel condition lever. While the propeller control provided some response, the engine continued to produce excessive thrust. The pilot performed a large orbit around the island, attempting a shallow descent and deploying flaps to increase drag.
During the final approach, the pilot maintained a high airspeed of 147 knots, significantly above the recommended 75–85 knot range. The pilot expressed concern to air traffic control regarding the proximity of populated resort buildings and maintenance structures at the runway end. The aircraft reached the runway threshold at 123 knots and touched down at approximately 100 knots, two-thirds of the way down the runway. Despite maximum braking, the aircraft overran the runway at 92 knots, traveling across sandy soil and vegetation until the left wing struck the ground, causing the aircraft to flip and come to rest inverted. There were 10 occupants on board, all of whom escaped with minor injuries, though the aircraft was a total loss.
Findings
- The engine experienced an uncontrollable overspeed characterized by excessive torque and interstage turbine temperature.
- The pilot's approach speed was significantly higher than the manufacturer's recommended parameters for full flaps.