What happened
On 22 September 2010, a private helicopter flight traveling from Margate to Port Alfred made a scheduled stop at the Kob Inn Beach Resort in the Eastern Cape. After a break for breakfast, the pilot and a passenger prepared for the next leg of the journey.
The pilot initiated a hover in prevailing crosswind conditions, noting a manifold pressure of 25” which appeared adequate for a vertical departure. However, as the pilot turned the aircraft into the wind to execute a steep take-off, the low rotor RPM warning horn activated. Despite attempts to restore engine power and adjust the collective, the rotor RPM continued to decay, leading to a loss of altitude. The Schweizer 269C-1, registration ZS-REU, subsequently struck a wooden jungle gym structure, causing the aircraft to roll onto its right side.
The investigation
An investigation by the SACAA AIID established that the aircraft was properly maintained and held a valid certificate of airworthiness. Meteorological data from the South African Weather Services confirmed that the area was experiencing strong surface winds and moderate to severe turbulence at the time of the incident. The investigation also noted that the pilot and passenger were properly restrained by seat belts and shoulder harnesses, which contributed to their ability to escape the wreckage without any injuries.
Findings
- The primary cause of the accident was the impact with a wooden obstacle following a decay in main rotor RPM during the transition to flight.
- The pilot failed to use sufficient collective pitch to prevent a loss of altitude during the transition.
- Severe weather conditions, including turbulence and strong winds, were present at the site.
- The aircraft sustained substantial damage to its skids, tail boom, tail rotor, and main rotor blades.