What happened
On 10 June 2015, a Flight Design CTSW, registration G-CGIZ, was performing a private flight returning to Manchester Barton Aerodrome from Haydock Park. The weather conditions were favorable, with winds ranging from calm to 15 knots.
As the pilot was on short final for the grass runway 08, approximately 5 feet above the ground, the left wing suddenly lost lift. In response, the pilot applied full power and used right rudder, which caused the aircraft to climb to an altitude of roughly 15 feet in a standard climbing attitude. However, as the pilot attempted to level the wings using right aileron, the left wing dropped abruptly a second time. This caused the aircraft to enter a 180-degree turn with a bank angle of approximately 30 degrees. Now flying downwind and descending, the pilot determined a ground impact was unavoidable and closed the throttle. The aircraft's left main wheel struck the ground with significant force, causing the wheel spar to break. The aircraft subsequently settled on the grass, sustaining moderate damage to the left underside and the propeller. The pilot sustained no injuries.
The investigation
The investigation was based on the aircraft accident report submitted by the pilot. Investigators examined the sequence of the wing drops and the pilot's subsequent recovery attempts. The investigation looked into the aircraft's performance during the climb and the potential for aerodynamic stalls or environmental factors like windshear.