What happened
On 4 September 1999, a Bell 206B helicopter, registration ZS-REK, was engaged in a commercial inspection of power lines. While operating approximately 35 km south-east of Copperton, the aircraft struck a wire that was stretched across the power lines being inspected.
Following the impact, the pilot successfully performed an autorotation to bring the aircraft down. However, during the landing sequence, the helicopter skidded forward across the terrain. The front of the skids became embedded in the sand, causing the aircraft to tilt forward onto its nose. This movement resulted in the main rotor making contact with the tail boom, which ultimately severed the boom from the rest of the airframe.
The investigation
Investigators examined the circumstances surrounding the collision and the subsequent structural failure of the aircraft. The inquiry established that the weather conditions at the time of the incident were fine. The investigation also reviewed the pilot's credentials and found that the pilot-in-command was operating with an invalid commercial license, as they did not possess a valid medical certificate at the time of the accident. There were 0 fatalities and 0 injuries reported following the event.
Findings
- The primary cause of the accident was the collision with a wire positioned across the power lines under inspection.
- The structural failure of the tail boom was caused by the main rotor striking it after the aircraft tipped forward during a landing skid.
- The pilot was operating without a valid medical certificate, rendering their flying license invalid.