Accident Details
On August 3, 2024, at approximately 1427 local time, a Sling LSA ultralight aircraft, registration SA2022, operated by the Chinese Taipei Sport Flying Development Association, crashed during takeoff from the Jiehao activity site in Gaoshu Township, Pingtung County. The aircraft departed from runway 26 at 1426. During the takeoff roll, rotation began at about two-thirds of the 300-meter runway, and the main wheels lifted off near the end of the runway. After becoming airborne, the aircraft flew along the runway heading for about 15 seconds, then began a right turn. Four seconds later, it rolled right with the nose dropping, and five seconds after that, it descended below treetop level and crashed into a betel nut orchard west of runway 08 threshold. The aircraft sustained substantial damage; the two occupants (pilot and one passenger) were not injured.
Aircraft Information
The accident aircraft was a Sling LSA, a low-wing, single-engine, side-by-side two-seat ultralight manufactured by Sling Aircraft (South Africa). It had a fixed tricycle landing gear and was powered by a Rotax 912 iS engine driving a three-blade carbon fiber propeller. The aircraft had a valid ultralight inspection certificate (CAA-111-008, valid until November 13, 2025). Total airframe time was 1,498.1 hours; engine time was 1,487.4 hours. The maximum takeoff weight was 600 kg. For the accident flight, the pilot weighed 70 kg, the passenger 75 kg, and fuel (35 liters of 98 unleaded gasoline) weighed about 25 kg, resulting in a takeoff weight of 595 kg. The center of gravity was within limits (26.055% MAC, allowable 20%-33%). The aircraft had five engine intake protective plugs; one red plug was found at the crash site.
Pilot Information
The 61-year-old male pilot held a valid ultralight instructor certificate issued by the Civil Aeronautics Administration, valid until December 4, 2024. He had approximately 5,000 total flight hours, with 250-300 hours on the Sling LSA type. His most recent medical examination (dated October 25, 2022) was normal. No alcohol test was conducted on the accident day. The pilot reported that he had removed the pitot tube cover during preflight but did not notice the engine intake plugs.
Engine and Performance Data
Data from the engine control unit (ECU) showed no fault events during the accident flight. However, performance data indicated significantly lower engine output compared to a previous flight: at full throttle, engine speed reached only about 4,300 rpm (vs. 5,500 rpm), manifold pressure 75 kPa (vs. 99 kPa), fuel flow 77 g/min (vs. 160 g/min), and intake airflow 2,000 g/min (vs. 4,000 g/min). About 37 seconds after applying full throttle, the throttle was rapidly reduced to idle, after which the engine stopped. Post-accident examination of the engine revealed no mechanical anomalies; spark plugs showed normal combustion color, compression was present on all cylinders, and there was no abnormal debris. An intake protective plug was found in front of the engine air inlet. A simulated test with the plug installed on a similar engine showed that at full throttle, maximum RPM was below 4,500, mimicking the underperformance observed.
Investigation Findings
- The accident aircraft was on its first flight of the day. The pilot had flown another aircraft earlier that morning.
- Witnesses reported that the aircraft's pitch attitude after takeoff was unusually high, and the engine sound was quieter than normal.
- The aircraft's flaps were found at 10 degrees (Position 1).
- The cockpit throttle was found at a mid position, and both fuel boost pumps were off.
- The investigation did not determine the exact reason for the engine power loss, but the presence of the protective plug was noted.
- The pilot stated that during the takeoff climb, airspeed increased slowly, reaching only 55 knots instead of the expected 65 knots, and the aircraft could not climb above obstacles.
- No mechanical malfunctions other than the potential ingestion obstruction were identified.
- The pilot and passenger were uninjured.
The aircraft's flight data and witness statements indicate that the engine was not producing expected power during takeoff, which limited climb performance. The protective plug found at the scene suggests that an intake obstruction may have been present, but the report does not establish a direct causal link.