What happened
On the morning of 19 August 2012, a private flight was conducting maneuvers near a private landing area in the Bucklands area of Douglas, Northern Cape. The flight involved a EUROCOPTER AS 350 B3, registration ZS-HIW, carrying two occupants, both of whom were qualified pilots.
During the return leg of the flight, the pilot in command encountered difficulties while attempting to land. In response to these difficulties, the second occupant, the pilot's husband, requested to take control of the aircraft to assist with the landing. During the transition of control between the two pilots, the helicopter experienced a violent 180-degree yaw.
Upon taking command, the second pilot immediately increased power to regain altitude and maneuver away from the landing site. However, as power was applied, the aircraft began a rapid anti-clockwise yaw. The helicopter entered a series of 360-degree left-hand rotations before ultimately striking a house and subsequently hitting a hangar. The aircraft came to rest on the side of the hangar, and the EUROCOPTER AS 350 B3 was destroyed.
The investigation
SACAA AIID investigators examined the sequence of events leading to the impact, noting the meteorological conditions at the time. The weather was characterized by strong winds, with a 26-knot wind from 020 degrees, though visibility was good and cloud cover was minimal. The investigation focused on the transition of control between the two pilots and the subsequent aerodynamic behavior of the aircraft during power application.
Findings
- The primary cause of the accident was the impact with a building during a landing attempt conducted in high wind conditions.
- The sudden yaw of the aircraft was exacerbated by incorrect flight control inputs applied during the increase of engine power.
- The accident resulted in one serious injury and one minor injury among the occupants.