What happened
On 12 November 2021, a Piper 25-235 with registration ZS-MDO was performing a repositioning flight between two farm airstrips in the Free State province. The flight originated from the Kiesmet farm airstrip in Theunissen and was intended to land at the Mooipan farm airstrip. The operation was conducted under Visual Flight Rules (VFR) as a private flight.
After successfully landing on Runway 35 at Mooipan farm, the pilot began taxiing toward the hangar at a very low speed of approximately 5 to 10 knots. As the aircraft was roughly 75 metres from the hangar, a sudden gust of wind caught the tail of the plane. This force caused the aircraft to veer sharply to the left of the runway. Although the pilot attempted to use the brakes to maintain control, the wind strength caused the aircraft to drift off the runway edge. The right wing subsequently struck a fence located about 2 metres from the runway, causing the left wing tip to drop and resulting in damage to the fabric on both wings.
The investigation
The investigation examined the environmental conditions and the aircraft's movement during the taxi phase. Meteorological data from the South African Weather Service at Welkom Aerodrome indicated that around the time of the incident, winds were recorded at 260 degrees at 14 knots, with gusts reaching 24 knots. This resulted in the aircraft being subjected to a crosswind component of 25 knots, which exceeded the aircraft's maximum rated crosswind component of 15 knots.
Findings
- The aircraft was taxiing at a very low speed (5–10 knots) when the incident occurred.
- A strong wind gust caused the tail to move, leading to a sharp leftward veer.
- The crosswind component of 25 knots significantly exceeded the manufacturer's specified limit of 15 knots.
- The pilot's attempt to correct the deviation using brakes was insufficient to counteract the wind force.
- The aircraft sustained substantial damage to the wing fabric and wing tips.