What happened
On 31 January 2012, a Robinson R44 helicopter, registration ZS-HGH, was conducting a private flight from the Indlelo Conference Centre in Witbank toward Nelspruit Aerodrome. During the initial phase of flight, the pilot successfully cleared a ground wall by turning the aircraft into the wind. However, as the helicopter transitioned into flight, the main rotor RPM warning light activated.
As the aircraft approached electrical cables located approximately 100 meters from the takeoff point, the pilot attempted to maneuver around the obstacles. In the process of pitching the nose up to ensure clearance of the 5-meter-high cables, the main rotor RPM decayed further. Realizing the situation, the pilot initiated a forced landing in a nearby open field. The aircraft struck the ground with significant force, hitting a mound of excavated soil. The impact caused the skids and the tail boom to separate from the fuselage, and the helicopter subsequently rolled over. There were no injuries to the pilot or the two passengers on board.
The investigation
An investigation by the SACAA AIID examined the aircraft's mechanical state and the pilot's actions. The Robinson R44 was found to have been properly maintained, with a valid Certificate of Airworthiness and Certificate of Registration. Subsequent inspections at an approved maintenance organization revealed no mechanical or system failures that contributed to the incident.
Findings
- The primary cause of the incident was an unsuccessful forced landing following a decay in main rotor RPM.
- Poor flight technique while attempting to clear obstacles after takeoff directly led to the rotor RPM decay.
- The pilot's decision to pitch the aircraft up to avoid electrical cables increased the angle of attack, which exacerbated the loss of rotor speed.