What happened
On the morning of 5 February 2022, a Scheibe SF-25C Falke motor glider, registered ZS-GYK, departed from Potchefstroom Aerodrome in the North West Province for a local flight. The flight, conducted under Part 9 and 4 regulations, was intended to be a short circuit returning to the same aerodrome.
During the landing phase on Runway 03, the aircraft's propeller made contact with the runway threshold edge. While the pilot managed to maintain control of the aircraft throughout the subsequent landing roll, the impact caused substantial damage to the wooden propeller blades and caused the tail wheel to detach from the airframe. The pilot escaped the incident without injury.
The investigation
An investigation into the incident examined the flight conditions, the pilot's approach, and the aircraft's performance. At the time of the occurrence, weather conditions were fine, though a METAR report indicated a light crosswind component for Runway 03.
The investigation reviewed the pilot's credentials, noting a valid Glider Pilot Licence with the appropriate type endorsement and a current Class 2 medical certificate. The pilot had accumulated 111.7 total flying hours, with 66.9 hours specifically on the Scheibe SF-25C Falke.
Findings
Technical analysis of the approach revealed that the pilot maintained an approach speed consistent with the manufacturer's recommendation of 49 knots. However, the investigation established that the pilot did not increase this speed to account for the prevailing crosswind.
As a result, the aircraft's airspeed dropped 10 to 20 km/h below the necessary threshold for a stable crosswind landing. This reduction in speed led to a stall just above the ground, causing the aircraft to undershoot the runway and strike the threshold edge with the propeller.