What happened
On 12 June 2012, a weight-shift powered ultralight vehicle, registration S1045, crashed into reclaimed land in Songdo-dong, Yeonsu-gu, Incheon-si. The aircraft, a S1045 (Top14.9) operated by the Songdo Flight Club, was conducting an experience flight with one pilot and one passenger on board.
During the flight, the pilot attempted a left descending turn at a low airspeed. During this maneuver, the aircraft was influenced by a strong tailwind and a natural tendency to drift toward the inside of the turn. This caused the vehicle to enter a stall and adopt a steep diving attitude. While the pilot attempted to recover the aircraft at a low altitude, the vehicle entered a right spin and struck the ground. The accident resulted in two fatalities.
The investigation
The ARAIB examined the wreckage, the engine, and the flight history of the aircraft. Investigators performed a teardown inspection of the engine, which revealed no mechanical anomalies or impact marks on the gearbox that would suggest an engine failure prior to impact. However, the investigation noted that the aircraft's fuel tank was made of opaque plastic and lacked any instrumentation to allow the pilot to monitor fuel levels during flight.
Furthermore, the investigation found that the aircraft's wing type was recorded incorrectly in its safety certificate. The investigators also reviewed the maintenance and installation history, noting that certain components had been installed in positions contrary to the manufacturer's manual. The investigation also looked into the regulatory environment, noting a lack of specific legal frameworks for managing ultralight airfields and restricted flight areas in the region.
Findings
- The pilot performed a descending turn without adequately accounting for the wind conditions, the specific aerodynamic characteristics of the wings, or the remaining fuel quantity.
- The aircraft's fuel tank design and lack of gauges prevented the pilot from verifying fuel levels during the flight.
- As the aircraft's bank and descent angles increased, the remaining fuel shifted within the tank, which likely led to an engine malfunction.
- The pilot was not sufficiently familiar with the aircraft's emergency equipment, including the emergency parachute system.
- The aircraft's safety certification contained inaccurate information regarding the wing type.