What happened
On the morning of 12 February 2014, a Robinson R44 Raven II helicopter, registration ZS-PXP, departed from Setlakgole aerodrome in the North West province for a scheduled game culling operation. The flight, operated by Maf Toy Auto CC, included the pilot and one passenger.
Approximately 35 minutes into the flight, while cruising at an altitude of 60 metres above ground level, the pilot experienced a sudden loss of engine power. Despite attempts to recover the aircraft by applying power via the throttle, the helicopter could not maintain its altitude. The pilot was forced to execute an emergency landing in dense, bushy terrain near Farm Stella in the Mahikend area. During the impact, the helicopter struck several small trees and landed heavily on its skids. The force of the landing caused the main rotor blades to sever the tail boom. While the aircraft sustained substantial damage, there were no injuries to the occupants.
The investigation
SACAA AIID investigators examined the wreckage and the engine components to determine the cause of the power loss. The investigation included a thorough inspection of the Lycoming engine, the fuel system, and the hydraulic assembly.
Testing of the engine and fuel samples revealed no contaminants or mechanical defects that could have caused an engine failure. The fuel filter was clean, and the engine was found to be capable of operating at full power during post-accident testing. The investigation also confirmed that the aircraft was within its maximum certified take-off weight and that all maintenance and licensing requirements were up to date.
Findings
- The pilot held a valid commercial license with the appropriate cull rating.
- The engine and fuel systems were found to be in good working order with no identified defects.
- The primary cause of the incident was the pilot inadvertently switching the hydraulic system OFF during flight. It is believed the pilot, while focused on the animals during the culling operation, mistakenly toggled the hydraulic switch on the cyclic control, believing it to be the siren switch. This action created significant handling difficulties that made the forced landing unavoidable.