What happened
On 9 August 2010, a Bantam Jabiru B22J microlight, registration ZU-EGU, departed from Hoedspruit civil aerodrome for a local daytime flight under visual flight rules. The flight, which included a pilot and one passenger, proceeded normally for approximately fifteen minutes until the aircraft experienced a sudden loss of power.
In an attempt to maintain flight, the pilot applied full throttle, but the engine RPM fluctuated before dropping to idle, rendering the aircraft unable to sustain level flight. The pilot immediately declared a MAYDAY, informed the passenger of the emergency, and identified a gravel road at Tshikode game farm as a potential landing site. However, during the final approach to the road, the engine failed completely, causing the pilot to lose control. The aircraft struck a roadside tree, spun 270 degrees, and came to rest on the opposite side of the road. The impact resulted in substantial damage to the aircraft's propeller, undercarriage, and right wing tip. The pilot sustained minor injuries, while the passenger was unhurt.
The investigation
SACAA AIID investigators examined the wreckage and the engine components to determine the cause of the power loss. The investigation confirmed that the weather conditions at the time of the accident were clear with good visibility and did not contribute to the event. The aircraft had been maintained according to approved procedures, with only 10 hours flown since its last annual inspection.
Technical analysis of the engine, which was transported to George for examination, revealed that the failure was mechanical in nature. Engineers identified that the engine's valves had become sticky due to the failure of the hydraulic lifters.
Findings
- The primary cause of the accident was an unsuccessful forced landing following an engine failure in flight.
- The engine failure was caused by failed hydraulic lifters, which led to sticky valves.