What happened
On the morning of 3 July 2022, a Van's RV-10 aircraft, registration ZU-IP and ZU-IPN, departed from a private airstrip in Molteno, Eastern Cape, for a return flight to Gauteng. The aircraft was carrying the pilot and three passengers. During the initial climb, at an altitude of approximately 75 feet above ground level, the aircraft encountered intense vibrations caused by powerful turbulent winds. This turbulence triggered an uncontrolled descent. Unable to recover the aircraft, the pilot executed a forced landing in an open field adjacent to the runway. During the landing roll, the aircraft struck a perimeter fence, which severed the fuel tanks and caused a significant fuel leak. Despite the substantial damage to the aircraft, all four occupants escaped without injury.
The investigation
An investigation by the SACAA AIID examined the aircraft's mechanical condition, the meteorological environment, and the regulatory compliance of the flight. Technical inspections of the engine and airframe revealed no mechanical or structural failures that would have prevented normal flight. Weight and balance calculations confirmed the aircraft was 150kg below its maximum take-off weight. Meteorological analysis from the South African Weather Service identified strong north-westerly winds and significant wind shear. The presence of mountain waves, caused by airflow interacting with nearby 7,000ft peaks, was confirmed as a primary factor in the atmospheric instability.
Furthermore, the investigation reviewed the aircraft's regulatory status. While the aircraft held a valid Authority to Fly (ATF) certificate, investigators found that the flight deviated from the specific restrictions of its proving flight certificate. Specifically, the aircraft was operated outside of its permitted 100-kilometre radius and was carrying passengers, which was prohibited under the terms of its current certification.
Findings
- The primary cause of the accident was the aircraft losing lift due to mountain wave turbulence encountered during the climb.
- The pilot's flight planning was insufficient for the prevailing atmospheric conditions.
- The aircraft was operated in violation of SA-CATS 24.02.3 regulations regarding flight radius and passenger carriage.
- There was no evidence of mechanical or structural anomalies in the engine or airframe.
- All occupants were wearing safety harnesses, which functioned as intended during the impact.