What happened
On the morning of 11 June 2024, a Cessna 182T Skylane, registration ZS-URO, departed from Mooketsi Airstrip near Tzaneen for a flight to Esme 4 Farm Airstrip. The aircraft was carrying a pilot and three passengers under visual flight rules.
While flying over the Giyani residential area, the engine began to oscillate and emit unusual noises, accompanied by a sharp rise in exhaust gas temperature. As the engine power progressively failed, the pilot attempted to descend through broken stratocumelus clouds to find clear air. Finding the engine unable to maintain power, the pilot executed an emergency landing on the D3732 public road. During the landing roll, the aircraft's left wing struck several trees, causing the wing and aileron to be severed. The nose gear subsequently collapsed, and the aircraft veered into the roadside bush. While the aircraft sustained substantial damage, there were no fatalities, though one passenger sustained minor injuries.
The investigation
The SACAA AIID conducted a desktop investigation into the occurrence. Investigators examined the aircraft's maintenance records, which showed the plane was within its inspection intervals and held a valid Certificate of Airworthiness. A post-accident examination of the engine at an approved facility found no mechanical defects, ignition issues, or fuel contamination. The investigation also confirmed the aircraft was within its maximum allowable takeoff weight. Meteorological data was analyzed, focusing on the temperature, dew point, and humidity levels at the time of the accident.
Findings
- The engine experienced serious carburettor icing, which caused the loss of power.
- Atmospheric conditions, including a temperature of 13°C and 79% relative humidity, were highly conducive to ice formation in the carburettor venturi.
- The presence of broken stratocumulus clouds likely exposed the aircraft to localized turbulence and icing conditions.
- The pilot's decision to land on the road was consistent with standard emergency procedures to protect the occupants.