What happened
On 19 October 2024, a Robinson R44 Raven II helicopter, registration ZS-PXS, was engaged in a private flight within the Limpopo province. The flight originated from Kwaggasvlakte Farm in Thabazimbi, heading toward the Limpopo River, with plans to return to the departure point. The flight was conducted under visual meteorological conditions during daylight hours.
After approximately two hours of flight time, while the pilot was returning to the farm at an altitude of 600 feet above ground level, the aircraft experienced a sudden loss of engine power. The pilot attempted to execute an autorotation to perform a forced landing; however, the helicopter struck the ground hard on its skid gear in bushy terrain approximately 10 nautical miles north of Kwaggasvlakte Farm. The impact caused substantial damage to the aircraft. The pilot, who was the sole occupant, was uninjured and able to exit the wreckage without assistance.
The investigation
SACAA AIID investigators conducted a post-accident examination of the engine and fuel systems. The investigation confirmed that the aircraft had sufficient fuel at the time of the accident, and the fuel was found to be free of contaminants. The fuel injection system, fuel filters, and gascolator were all inspected and found to be functioning correctly.
Mechanical examinations of the engine components, including the engine casing, fuel control unit, and magnetos, revealed no evidence of pre-impact mechanical failure or malfunction. A bench test of the engine showed it could start and run normally. Furthermore, the investigation found no issues with the engine's ignition switch or the grounding wires of the magnetos. Despite these extensive checks, the specific reason for the sudden loss of engine power remained unidentified.
Findings
- The primary cause of the accident was an undetermined loss of engine power.
- A contributing factor may have been the decay of the main rotor RPM below the required 97% limit during the flight.
- The aircraft had undergone a mandatory 100-hour inspection earlier in the year and was in a valid state of airworthiness.