What happened
On the morning of 20 December 2011, a Bell 206B helicopter, registration ZS-HHW, departed Wonderboom aerodrome for a private flight to Bakubung bush lodge. The flight, operated by a single pilot, proceeded normally through the initial climb. After communicating with Pilanesberg ATC and receiving clearance to cross the runway 23 centerline, the pilot was requested to report his arrival at his destination. However, no further communication was received.
Eyewitnesses observed the aircraft flying at a low altitude of approximately 330 feet AGL south of the Sun City complex. The helicopter struck a zip line cable that spans from the top of Sun City Mountain. The impact with the lower windshield caused a loud noise and sent the aircraft into a descent, where it crashed near the base of the mountain. The impact destroyed the aircraft and resulted in one fatality.
The investigation
An investigation by the SACAA AIID examined the wreckage and interviewed witnesses. Investigators found that the helicopter's engine and mechanical systems were operating normally prior to the collision. The aircraft was properly maintained, with a valid Certificate of Airworthiness and recent maintenance inspections. Weather conditions at the time were clear with good visibility.
Analysis of the wreckage confirmed the cable struck the lower windshield. The force of the impact was so severe that the pilot was thrown from the aircraft, and the safety harness failed during the deceleration. The investigation also reviewed the Aeronautical Information Publication (AIP) for Pilanesburg, which identifies the zip line as a known hazard and prohibits flights below 2,000 feet in that specific area.
Findings
- The primary cause of the accident was the collision with the zip line cable spanning from Sun City Mountain.
- The pilot was flying in an area where the zip line was officially documented as a hazard in the AIP.
- The pilot likely failed to consult the necessary aeronautical publications, such as the AIP or NOTAMs, which would have identified the restricted airspace and the presence of the cable.
- The aircraft was in a valid state of airworthiness and was maintained according to manufacturer standards.