What happened
On 17 October 2022, a Mooney Aircraft Corporation M20J, registration VH-UDQ, departed Maitland Airport, NSW, for a local flight. While flying near Luskintyre airfield, the pilot signaled an intention to return to Maitland. However, witnesses observed the aircraft descending toward Luskintyre while trailing flames and smoke. The aircraft touched down in a grass field before striking a line of trees, causing an explosion and a large fireball. The pilot sustained serious injuries and died 10 weeks later. The aircraft was destroyed in the crash.
The investigation
The investigation focused on the cause of the in-flight fire and the condition of the engine components. Investigators determined that fuel leaked from the outlet fitting of the engine-driven mechanical fuel pump. This leak was caused by an O-ring seal that had deteriorated due to age, allowing fuel vapors to escape and ignite from heat within the engine compartment.
Data showed a rapid descent from 1,522 ft to 52 ft in just 50 seconds. While the pilot attempted an emergency landing, the engine was still rotating at a speed inconsistent with a power-off configuration. The high descent rate and ground speed made the subsequent collision with the trees unavoidable. Additionally, investigators noted that the aircraft had undergone recent interior refurbishment, but there was no documented flammability assessment for the new materials used in the cabin.
Findings
- The engine compartment fire was caused by fuel escaping from a degraded O-ring seal on the fuel pump outlet.
- The pilot's emergency descent toward Luskintyre airfield was characterized by a very high rate of descent.
- The aircraft's fuel pump O-ring seals were maintained on a condition-based basis rather than being replaced at fixed intervals, and the seals were not easily visible for inspection.
- The lack of documentation regarding the flammability of new interior furnishings increased the risk of fire spread.