History of the Flight
On the morning of 20 December 2011, a private helicopter flight departed Wonderboom aerodrome (FAWB) in Gauteng province. The pilot was the sole occupant. The destination was Bakubung bush lodge in North West province. No flight plan was filed. According to the FAWB air traffic controller, the climb-out was uneventful. En route, the pilot communicated with Pilanesberg ATC and was cleared to cross the extended centerline of Runway 23. The pilot was instructed to report on final approach to Bakubung, but no further communications were received.
Three eyewitnesses observed the helicopter heading south of the Sun City complex at a low altitude, approximately 330 feet above ground level. The helicopter collided with a zip line cable on its lower windshield. Witnesses reported that the engine sounded normal, and a loud bang was heard immediately after impact. The cable swung sideways, and the helicopter descended to the ground near the foot of Sun City Mountain. One witness, an employee at Sun City at the zip slide bottom station, contacted the zip line operator, who alerted the South African Police Services and Emergency Medical Services. First responders secured the area.
Aircraft and Personnel Information
The helicopter involved was a Bell 206B, registration ZS-HHW, serial number 2551, manufactured by Bell Helicopter Textron in 1978. The owner was Evening Star Trading 579 (PTY) LTD. The total airframe hours were unknown, but the last Hobbs meter reading before departure was 1612.6 hours; post-accident, it read 1613.5 hours, indicating 0.9 hours flown. The engine was an Allison 250 (serial CAE.822773) with 6209.8 hours since new and TBO not reached. The last maintenance inspection (MPI) was conducted on 7 April 2011 at 13,317.9 hours.
The pilot was a 52-year-old South African male holding a valid private helicopter license (number 0270261969) with a type endorsement for the Bell 206B. His total flying hours were unknown; the last recorded total from his license renewal in July 2011 was 534.7 hours. He had a prior incident in December 2006 involving a main rotor blade strike after encountering a gust of wind.
Accident Site and Wreckage
The accident occurred near the foot of Sun City Mountain at GPS coordinates South 25° 21.411´, East 027° 05.407´, during daylight conditions at 0750Z. The weather was clear with temperature 27°C, dew point 12°C, surface wind 05 knots, and visibility 10 km.
The helicopter struck the zip line cable on the lower windshield. The cable did not fail. The tail boom was destroyed on ground impact, and the tail rotor gearbox detached. The fuel tank ruptured, and a smell of Jet A1 fuel was present. The engine and main rotor examination indicated normal operation prior to impact. All doors detached and were severely damaged. The cockpit instrument console was severely damaged. The helicopter was destroyed. The pilot was fatally injured; his body was found approximately 80 meters from the wreckage, having been thrown from the aircraft after the cable collision.
The zip line facility (adventure slide) was not operational at the time; its operating hours were 09:00, 11:00, 13:00, and 15:00. The cable spanned from a launching platform 280 meters (924 feet) high on the mountain top to a receiving platform approximately 2 kilometers away.
Injuries
The pilot sustained fatal injuries. No other persons were on board or injured.
Damage
The helicopter was destroyed. The zip line cable sustained damage but did not fail.
Probable Cause
The aircraft collided with the zip line cable spanned from Sun City Mountain top, rendering ground impact inevitable.