What happened
On 28 September 2016, a Bell 206B helicopter, registration ZS-RFC, was performing game counting operations in the Limpopo Province. After completing several flights at the ZZ2 Game Farm, the crew refuelled the aircraft with the intention of returning to their base at Tankerton Farm.
Shortly after departing ZZ2 Game Farm at approximately 1450Z, the crew member noticed an unusual noise suggesting the engine was losing power. Within minutes of takeoff, the aircraft began a rapid descent. The pilot attempted to execute an autorotation to land in a nearby dry river bed, but the maneuver was unsuccessful. The helicopter struck trees before impacting the ground at high velocity. A post-impact fire broke out, fueled by a ruptured tank. While the crew member managed to escape the burning wreckage with serious injuries, the pilot succumbed to his injuries due to burns and smoke inhalation.
The investigation
SACAA AIID investigators conducted a detailed examination of the wreckage and the Rolls Royce 2/50-C20J engine. Metallurgical testing of the turbine module revealed that a blade from the second stage turbine wheel had separated. This separation was caused by progressive fatigue cracking.
Further analysis of the engine components showed evidence of thermal degradation and damage from the ingestion of foreign objects, specifically sand and small pebbles. The investigation also noted that the aircraft's wreckage distribution indicated a high forward speed and rate of descent at the moment of impact, suggesting the pilot had insufficient altitude and time to effectively flare the aircraft or avoid obstacles.