What happened
On March 16, 2023, at approximately 15:18 local time, a Shark LSA ultralight aircraft, registration SF255．5, crashed into a sandbar of the Zhuoshui River in Changhua County, Taiwan. The aircraft, operated by the Shun Feng Flying Association, was performing a low-approach maneuver at the Shun Feng activity airfield.
After passing the runway threshold, the pilot attempted a climb and turn. During this maneuver, the aircraft's airspeed dropped below the required safety margins. Video evidence and GPS data indicate the aircraft experienced two distinct periods of aerodynamic buffet, signaling an impending stall. While the aircraft initially leveled its pitch, the pilot retracted the flaps while the airspeed was still insufficient. This caused the aircraft to lose lift and descend. The left wing subsequently dropped sharply, leading to a full stall and a crash at an altitude of approximately 48 meters. Both occupants, the pilot and a passenger, were killed in the impact and subsequent fire.
The investigation
The Taiwan Transportation Safety Board (TTSB) conducted a thorough examination of the wreckage, engine components, and flight data. Investigators analyzed ground-based witness videos and onboard cockpit footage, synchronizing them with GPS logs. The investigation included a spectral analysis of engine audio from witness recordings, which confirmed the engine was operating at approximately 4,800 RPM and remained functional until impact.
Physical inspections of the wreckage revealed that the flaps were in the retracted position at the time of the secondary stall. The engine, a Rotax 912 ULS, showed no signs of mechanical failure or internal damage. Investigators also reviewed the pilot's training records, the aircraft's maintenance history, and the operational procedures of the flying association.