Primary finding
Probable cause
The bent tailwheel spring that allowed the tailwheel to caster when the airplane encountered a wind gust on landing roll.
Investigator assessment
Analysis narrative
On downwind, the pilot noticed that the wind had increased and that there was light turbulence. He planned to land beyond some trees to avoid turbulence. The airplane encountered a wind gust during the landing roll. The pilot applied rudder and aileron corrections along with heavy braking. The airplane exited the runway and impacted a pipe rack resulting in substantial damage to the left wing. A postaccident examination of the airplane revealed that a tailwheel spring was bent, and its spring rate was weak, which allowed the tailwheel's fork to caster freely by not engaging into its machined locking detent.
Source record
Factual narrative
On downwind the pilot noticed that the wind had picked up and that there was light turbulence. He planned to land beyond trees to avoid turbulence. The airplane went through a gust of wind on roll out. The pilot applied rudder and aileron corrections along with heavy braking. The airplane exited the runway and impacted a pipe rack where the airplane sustained substantial damage to its left wing. A postaccident examination of the airplane revealed that a tailwheel spring, part number 3432, was bent and its spring rate was weak, which allowed the tailwheel's fork to caster freely by not engaging into its machined locking detent.