What happened
On 25 July 2022, a private flight involving a Sling 2 aircraft, registration ZU-FNN, was conducting a local circuit at Morningstar Aerodrome in the Western Cape. The flight, operated under Part 94 regulations, was returning to the aerodrome for landing under clear visual meteorological conditions.
During the final approach to Runway 20, the aircraft was flying at an indicated airspeed of 74 knots. As the aircraft passed over trees located near the runway threshold, it encountered wind shear at approximately 100 feet above the ground. This disturbance caused the aircraft to drift right of the centerline. While the pilot attempted to correct the deviation using rudder and aileron inputs, the aircraft bounced twice upon touchdown. This instability led to a loss of control, causing the aircraft to veer off the runway into a soft sand area. The nose wheel sank into the sand, causing the propeller to strike the ground and the nose gear strut to collapse under the resulting load. There were no injuries to the two occupants, though the aircraft sustained substantial damage.
The investigation
SACAA AIID examined the flight parameters and aircraft maintenance history. The investigation confirmed that the pilot held a valid Private Pilot Licence and a current Class 2 medical certificate. The aircraft's maintenance records showed that the most recent mandatory periodic inspection had been completed roughly one month prior, with 11.5 flight hours remaining before the next scheduled inspection.
Findings
- The pilot's approach speed of 74 knots was 2 knots higher than the 72-knot best glide speed recommended in the Pilot’s Operating Handbook.
- The aircraft was unstable on approach, which directly led to the subsequent hard landing and multiple bounces.
- The encounter with wind shear near the runway threshold contributed to the initial deviation from the centerline.