What happened
On July 5, 2002, a Jabiru SP, registered ZU-SES, was conducting a commercial geographical survey flight. While operating near Ellisras Aerodrome, the pilot experienced a sudden degradation in engine performance, characterized by rough running and a partial loss of power. During this period, the pilot noted an increase in engine oil temperature and detected the smell of hot metal.
Recognizing the developing mechanical issue, the pilot aborted the survey mission and initiated a return to the departure point. The pilot successfully executed a safe landing back at Ellisras Aerermodrome. Following the shutdown of the engine, an attempt to manually rotate the propeller was made, but the engine would not move.
The investigation
Following the incident, an Aircraft Maintenance Engineer (AME) was called to inspect the aircraft. Because the engine appeared to have seized during operation, a teardown inspection was performed to identify the source of the mechanical failure.
Findings
- The investigation determined that the exhaust valve in the No. 3 cylinder failed due to fatigue.
- This primary valve failure led to secondary internal damage within the engine.
- The resulting internal damage ultimately caused the engine to seize while in flight.