Accident Overview
On 16 March 2023 at approximately 15:18 local time (UTC+8), a Shark LSA ultralight aircraft, registration SF2555, operated by the Shunfeng Flying Association (SFA), crashed into a sandbar in the Zhuoshui River south of the SFA's activity site in Xizhou Township, Changhua County, Taiwan. The aircraft was destroyed by impact and post-crash fire. Both occupants—a 54-year-old male pilot and his Japanese passenger—died.
Aircraft and Crew Information
The aircraft was a Slovak-made Shark LSA, serial number 109, manufactured on 1 September 2021. It was a single-engine, tandem two-seat fixed-wing ultralight with composite construction and fixed tricycle landing gear. The engine was a Rotax 912 ULS (serial 9574996), a four-cylinder horizontally opposed engine rated at 100 HP at 5,800 RPM. The propeller was a three-blade Woodcomp SR200 with ground-adjustable pitch. The aircraft had a maximum takeoff weight of 580 kg; its empty weight after paint and weighing was 344.6 kg. On the accident flight, the pilot (83 kg) and passenger (70 kg) were aboard with 57 liters (41 kg) of 95-octane gasoline, giving a takeoff weight of 538.6 kg.
The pilot held a valid ultralight instructor certificate issued by Taiwan's Civil Aviation Administration (CAA). He was a former military pilot with 1,936 military flight hours and 39.8 hours on type, totaling 1,975.8 hours. His medical examination was normal. Toxicology tests detected no drugs; his blood alcohol level was 23 mg/dL, but no alcohol was found in urine. The passenger was a Japanese national; no further details were provided in the report.
Accident Sequence
The flight departed from the SFA activity site at 15:00. The pilot flew over the Zhuoshui River area. At 15:17, he performed a low approach to runway 25. After crossing the threshold of runway 07, he initiated a go-around, climbing and turning left. At an altitude of about 48 meters, the aircraft began to descend and subsequently crashed onto a sandbar south of the field at 15:17:46. According to GPS data, the aircraft's ground speed during the low approach was about 103 km/h, and during the climb turn it decreased to around 84 km/h. Witness video showed the aircraft with flaps extended during the low approach, then retracting the flaps during the climb. The aircraft exhibited buffeting before the descent.
Investigation
Examination of the wreckage revealed that the aircraft struck the ground at an angle of about 50 degrees, with the left wing slightly lower. The engine was embedded in the sand. All three propeller blades were broken at the root, with blade edge deformation consistent with rotation at impact. The flap actuator was found in the fully retracted position. The engine showed no pre-impact anomalies; magnetic plug metal debris was within acceptable limits.
Video analysis from ground and onboard cameras (downlinked) showed that during the go-around, the aircraft's pitch attitude exceeded 25 degrees, then decreased to about 5 degrees as the aircraft sank. The aircraft rolled left up to 60 degrees before impact. Engine sound spectrogram analysis, compared to a same-type aircraft, indicated no abnormal engine operation.
Interviews with SFA personnel revealed that the club's pilots, including the accident pilot, had not been trained in stall recovery because the club avoided stall conditions per manufacturer guidance. The aircraft flight manual prohibits entering stalls and provides a recovery procedure requiring nose-down pitch and full power.
Regulations and Manuals
The aircraft was operated under Taiwan's ultralight vehicle regulations. The SFA's activity manual requires coordination with air traffic control before flights. On the accident day, there was no record of such coordination. The aircraft's flight manual specifies stall speeds: with flaps up, 45 knots (83 km/h); with flaps at 20°, 42 knots (78 km/h); 30°, 39 knots (72 km/h); and 40°, 38 knots (70 km/h). The manual prohibits stall/spin entries and notes that stall recovery requires a height loss of 450-500 feet.
Probable Cause
The investigation report does not state a probable cause.