What happened
On 11 August 2014, a Raven aircraft, registration ZU-FBL, was performing a precautionary runway inspection at a private airstrip on a farm in Hopefield, Western Cape. While flying at a very low altitude on the second approach to Runway 15, the aircraft encountered turbulence and lost height.
As the aircraft descended, the left wingtip and the left main landing gear struck nearby treetops. This contact caused the aircraft to rotate 270 degrees anticlockwise, resulting in a loss of control. The aircraft subsequently impacted the bushy terrain approximately 34 meters to the left of the runway. While the aircraft sustained substantial damage to its propeller, wings, undercarriage, and fuselage, the pilot and passenger escaped without injury.
The investigation
SACAA AIID investigators examined the flight path, weather conditions, and the pilot's approach technique. The investigation established that the aircraft was flying with a left quartering tailwind component. Evidence from the scene and witness photographs indicated that the aircraft was flying at an altitude lower than the surrounding trees, which significantly restricted the pilot's ability to recover from a sudden loss of height.
Investigators also reviewed the aircraft's maintenance records, finding that the ZU-FBL was properly maintained and equipped according to regulations. The investigation focused on the aerodynamic challenges presented by the airstrip's environment, specifically how the surrounding vegetation can create unpredictable airflow and turbulence.
Findings
- The pilot was flying at an unsafe altitude for the prevailing environmental conditions.
- The approach utilized a tailwind component, which made it difficult to maintain control during the loss of height.
- The aircraft's proximity to the treetops left insufficient margin for error when turbulence occurred.
- The primary cause of the accident was the disregard of standard operational procedures during the low-level runway inspection.
- Contributing factors included poor airmanship and inadequate technique during the inspection maneuver.