What happened
On 16 June 2002, a Jabiru microlight, registration ZU-BPR, was conducting a private flight from Upington Aerodrome toward Fisantekraal. While the aircraft was cruising at approximately 7,000 feet amsl near the Cederberg Mountains, the pilot detected a minor vibration in the engine. Shortly thereafter, the engine ceased operation.
The pilot attempted to restart the engine and was initially successful, though the engine continued to idle roughly at approximately 1,000 rpm. Although the application of carburetor heat temporarily improved engine smoothness, the engine suffered a complete failure as the pilot attempted to increase the engine rpm. Following a Mayday call, the pilot executed a forced landing on the rough, rocky foot of the Cederberg Mountains, roughly 25nm east of Citrusdal. The pilot, the sole occupant, was able to exit the wreckage uninjured.
The investigation
Investigators examined the aircraft's engine following the incident. A teardown inspection of the engine components was conducted to determine the nature of the mechanical failure.
Findings
- The primary cause of the engine failure was the fatigue failure of the No.3 cylinder exhaust valve.
- This valve failure caused significant secondary damage to the engine.
- The resulting mechanical damage led to a complete engine seizure, preventing continued flight.