What happened
While climbing through approximately 500 feet to clear low-level cloud, the aircraft experienced a power reduction that dropped below idle levels. Due to the low altitude at the time of the engine failure, the pilot had limited options for selecting a landing site. The resulting forced landing was performed into a paddock containing various obstacles with a downwind component. The impact resulted in substantial aircraft damage.
The investigation
Investigators identified a significant amount of water within the aircraft's fuel system components. While the engine showed no other mechanical defects, the presence of water suggested contamination as the primary driver of the power loss. During an inspection the day prior to the accident, water was found in the chemical hopper, suggesting that moisture could bypass the seal and lip to enter the system. Although the ferry fuel system was not in use during the flight, investigators considered that water could have entered the wing tanks during recent rainfall, as the tanks were only partially filled.
Further examination of the fuel control unit revealed additional contamination and grease washout, though it could not be definitively determined if this contributed to the fuel flow restriction. Engine data indicated that the engine did not surge during the power loss, suggesting that water droplets may have remained suspended in the fuel rather than separating.
Findings
- The methods used to check for water during pre-flight inspections—specifically using opaque containers and relying on sight and smell—did not align with CASA or FAA guidance. These methods were insufficient to detect suspended water droplets, which pose a specific risk in turbine fuel.
- The fuel drain performed on the morning of the flight may not have been effective in identifying water presence.
- It is possible that water separated from the fuel overnight as it cooled, and the changes in aircraft attitude during departure allowed this water to reach the fuel pickup.
- The use of the chemical hopper as a ferry tank was performed against the manufacturer's recommendations, and no approved technical data existed for this modification.
Safety message
When modifying safety-critical aircraft systems, it is essential to use approved and documented engineering processes. This ensures that any changes to the aircraft design comply with established airworthiness standards and maintain an equivalent level of safety.