Event
During the landing roll, the pilot lost directional control of the aircraft, which subsequently ground looped to the right. The incident occurred without any prior indication of mechanical abnormality.
Examination
A post-incident examination of the tail wheel assembly revealed a broken internal spring clip. The fracture surface exhibited features consistent with fatigue cracking, originating from several surface corrosion pits. Prior to disassembly of the tail wheel unit, it was observed that the unit would turn freely to the right but not to the left. Once the unit was disassembled and the broken spring clip was removed, the reassembled unit turned freely in both directions. This confirmed that the broken clip had restricted leftward movement, contributing to the loss of directional control during the landing roll.
The spring clip's failure mode—fatigue induced by corrosion pitting—indicates that the part had been subjected to cyclic loading over time, likely exacerbated by environmental exposure. The corrosion pits served as stress concentrators, initiating cracks that propagated until complete fracture occurred.
No other anomalies were noted in the tail wheel assembly or related components. The pilot's actions during the landing roll were consistent with normal procedure, and no pilot error was identified as a contributing factor. The investigation focused solely on the mechanical failure of the tail wheel spring clip.