What happened
While flying near Mallacoota Airport, the pilot began a descent from approximately 9,000 ft above mean sea level to navigate around low cloud cover. During this period, the aircraft's number 4 cylinder experienced fluctuating temperature readings. These fluctuations triggered warnings on the multi-function display, as the cylinder head temperature rose into the caution and warning ranges. In response to these indications, the pilot reduced engine power for a period before returning to normal power once temperatures stabilized.
Following a second period of temperature fluctuations, the pilot notified air traffic control of an intention to land at Moruya Airport, an unplanned diversion. However, after starting an approach to Moruya, the pilot abandoned the landing and continued the flight underneath the cloud base. Despite the presence of low cloud and instrument meteorological conditions in the area, the pilot proceeded toward the Great Dividing Range. The aircraft eventually struck rising terrain.
The investigation
Investigators examined the wreckage and flight data to determine the cause of the impact. The analysis confirmed that the engine was producing power up until the moment of collision. No evidence of structural failure or an in-flight break-up was found, and all major aircraft components remained at the accident site. The investigation determined that there were no pre-impact mechanical or airframe issues that contributed to the collision.
Findings
- The fluctuating cylinder head temperature warnings served as a persistent source of distraction, likely increasing the pilot's workload and reducing the ability to monitor navigation, weather, and terrain.
- The pilot's decision to deviate inland toward higher terrain was likely influenced by a temporary gap in the cloud cover visible in satellite imagery.
- The pilot, who had limited cross-country experience, entered weather conditions that were unsuitable for visual navigation.
- The pilot's loss of situational awareness led to the collision with terrain.