What happened
On 23 November 2018, a Cessna 150L, registration G-OKED, was conducting a private flight to verify the serviceability of the aircraft's radio equipment. During the return to Clipgate Farm Airfield, the pilot was approaching Runway 20 at an airspeed of 65 mph with the flaps set to 30°. Finding the aircraft higher than the desired glidepath, the pilot extended the flaps to 40° to increase drag. After stabilizing the descent, the pilot attempted to retract the flaps back to 30°, intending to use the configuration similarly to a glider's airbrake. However, the flaps were actually retracted to 20°.
During the final stages of the approach, sunlight obscured the pilot's view of the airspeed indicator. The landing flare lasted longer than anticipated, and the aircraft touched down on a damp grass surface. As the pilot applied the brakes, the aircraft skidded and eventually struck a hedge at the end of the runway. The impact caused the nosewheel to strike a tree stump, resulting in the collapse of the landing gear mounting tubes and damage to the engine cradle and propeller. There were no injuries to the pilot.
The investigation
The investigation examined the aircraft's configuration and the environmental conditions at the time of the accident. Investigators found that the flap setting was 20° rather than the intended 30°. The analysis also considered the impact of a potential tailwind component and the moisture levels of the grass runway. The pilot noted that while the windsock appeared limp, a tailwind might have been present above the tree line, and the runway surface was damper than initially perceived.