What happened
On September 21, 2011, at approximately 17:15, a STORCH S500 LSA ultralight aircraft crashed in a lychee orchard in Fenyuan Township, Changhua County. The flight originated from an unauthorized activity site in Xizhou Township, approximately 22 kilometers away.
After performing several practice landings at the departure site, the pilot flew toward the northeast. While circling over a residential area in Fenyuan, the pilot was observed making a telephone call to a friend. Witnesses reported that the aircraft was circling at a very low altitude, approximately 6 meters above the ground. During its fourth circuit, the aircraft suddenly slowed, tilted, and plummeted into the orchard. The impact with a lychee tree caused the aircraft to flip 180 degrees, rupturing the fuel tanks. The resulting fire consumed the entire aircraft. The pilot sustained severe burns over 95% of his body and passed away in the hospital on October 8, 2011.
The investigation
The investigation examined the wreckage, the aircraft's maintenance history, and witness testimonies. The aircraft, which featured a ROTAX 912 UL engine, had only 14 hours of total flight time and had been recently assembled from a kit. Investigators found no evidence of mechanical or engine failure, as witnesses noted the engine was still running immediately prior to the descent. The investigation also noted that the takeoff and activity areas used by the pilot were not approved by the Civil Aeronautics Administration.
Findings
- The primary cause of the accident was an aerodynamic stall occurring during a low-altitude turn, likely due to the pilot failing to maintain sufficient airspeed.
- The post-crash fire was caused by fuel escaping the wing tanks upon impact and coming into contact with the hot sections of the engine.
- The pilot was operating the aircraft without a valid ultralight pilot certificate.
- The flight took place within unauthorized activity airspace and at an unapproved landing site.
Safety action
- The investigation recommended that the Civil Aeronautics Administration increase inspections of unauthorized ultralight aircraft activities and coordinate with local governments to enforce regulations on unapproved activity sites.