What happened
On 14 June 2017, an MD 500E helicopter, registration ZT-RAC, was conducting a private flight from Welkom Airport toward Christiana. The pilot, accompanied by two passengers, intended to fly over the R700 regional road near Bultfontein to observe progress on ongoing road construction works.
While flying at approximately 80ft AGL, the pilot initiated a right-hand turn to follow the road. During this maneuver, the engine power was inadvertently cut, triggering an engine-out warning and an audible alert in the pilot's headset. The aircraft immediately experienced a loss of power, causing the nose to pitch and the aircraft to enter a right-hand spin.
In an attempt to manage the emergency, the pilot executed a forced landing on a nearby gravel road. During the flare, the rotor downwash created a significant dust cloud that obscured the pilot's vision and made it difficult to judge the ground height. The aircraft subsequently experienced a loss of tail rotor effectiveness, causing a violent swing to the right. The helicopter struck the ground hard, with the right skid gear breaking upon impact, resulting in substantial damage to the airframe and all five main rotor blades.
The investigation
SACAA AIID investigators examined the wreckage and the pilot's training records. Technical examinations of the engine and fuel system were conducted by the manufacturer and engine specialists; however, bench testing of the engine showed it was performing according to all manufacturer specifications, and no mechanical anomalies were found in the fuel system.
The investigation also focused on the pilot's recent transition from piston-engine helicopters to turbine-powered aircraft. Records indicated that the pilot had only accumulated 2.9 hours of flight time on the MD 500E type at the time of the accident. Furthermore, while the pilot had been cleared to fly solo for hour-building purposes, the formal aircraft type endorsement was still pending approval from the CAA.
Findings
- The primary cause of the power loss was the pilot inadvertently cutting off the engine power.
- The pilot applied an incorrect recovery technique, utilizing a twist-grip method characteristic of a Robinson R44 rather than the correct procedure for an MD 500E.
- The pilot's flight experience on the specific turbine-powered type was insufficient to safely manage the emergency.
- The heavy dust cloud generated during the landing flare contributed to the difficulty in judging the aircraft's altitude.
- The aircraft was maintained in accordance with all approved manufacturer procedures.
Safety action
Following the investigation, a recommendation was made to the Director of Civil Aviation to review the minimum flight hour requirements for pilots undergoing conversion training from piston-engine helicopters to more complex turbine-powered models.