What happened
On December 9, 2024, at approximately 10:55 local time, a Storch CL ultralight aircraft, registration JJ2258, crashed near the Jiahau activity site in Kaohsiung, Pingtung County. The aircraft, operated by the Taiwan Flying Players Sports Association, was carrying a pilot and one passenger.
After taking off from Runway 26, the aircraft climbed to an altitude of approximately 100 feet when the engine suddenly lost power. Video footage from the flight captured an object piercing through the engine cowling, followed by the immediate cessation of propeller rotation. Within seconds, the aircraft lost altitude and struck a roadside embankment and trees, coming to rest near a concrete pipe. The impact resulted in two injuries to the occupants, and the aircraft sustained substantial damage.
The investigation
The Taiwan Transportation Safety Board (TTSB) examined the wreckage and the engine, a Jabiru 2200A. An engine teardown conducted with the assistance of the manufacturer revealed that the fourth cylinder had suffered catastrophic failure. Specifically, investigators found that the piston pin's C-clip had detached, allowing the pin to move horizontally. This caused the pin to strike the internal crankcase flange during the piston's reciprocating motion, eventually leading to the piston and connecting rod breaking apart. The deformed connecting rod then pierced the upper crankcase housing and became wedged in the rotating crankshaft, causing the engine to stop instantly.
Investigators also reviewed maintenance logs and engine components. While the engine was relatively new, with only approximately 363 hours of operation, the investigation noted that some maintenance intervals, such as oil changes, did not strictly adhere to the manufacturer's specified schedule. Additionally, the engine was using an oil type not explicitly listed in the Jabiru maintenance manual.
Findings
- The primary cause of the accident was a mechanical failure in the engine where the C-clip securing the piston pin in the fourth cylinder detached.
- This detachment allowed the piston pin to shift horizontally, causing it to strike the engine structure and leading to the failure of the connecting rod.
- The failure of the connecting rod caused the engine to cease operation, resulting in the loss of power during the initial climb.
- Secondary factors included discrepancies in maintenance intervals and the use of non-specified engine oil.