What happened
On the morning of 10 March 2024, a Jabiru J430, registration ZU-URI, was conducting a private flight from Springbok Aerodrome to Morning Star Aerodrome. After an intermediate stop at Lamberts Bay, the aircraft departed for its final destination. While navigating the restricted airspace near Air Force Base Langebaanweg, the pilot engaged the carburetor heat multiple times to mitigate potential icing.
During this period, the pilot did not immediately notice that the engine was running rough and losing power. Once the power loss became apparent, the pilot attempted to restore engine function by cycling the magneto switches and activating the fuel pump, but these efforts were unsuccessful. To avoid a more critical situation, the pilot executed a precautionary landing in a densely vegetated field near the Elands Bay Nature Reserve. The impact resulted in substantial damage to the aircraft's landing gear and propellers, though there were no injuries to the pilot or the passenger.
The investigation
SACAA AIID investigators examined the aircraft and the environmental conditions at the time of the incident. Post-accident inspections by the maintenance organization revealed that approximately 30 litres of fuel had leaked from the wing tanks. While the aircraft's nose and main undercarriage sustained significant damage, the engine was later placed on a test bench, where it started immediately and performed correctly across all power settings. An inspection of the carburetor float bowl showed no signs of contamination from dirt or water.
Findings
- The primary cause of the engine failure was carburetor icing, which occurred as the engine lost power.
- Meteorological data indicated a relative humidity of 64%, creating a high probability of moderate icing during cruise and serious icing during descent.
- A contributing factor was inadequate flight planning, specifically the failure to calculate icing probabilities and implement necessary precautionary measures.