Primary finding
Probable cause
The pilot’s failure to maintain directional control during the landing rollout, resulting in a ground loop and runway excursion.
Investigator assessment
Analysis narrative
The pilot of the tailwheel equipped airplane reported that during the landing rollout and as the airplane slowed, rudder inputs became less effective. The airplane began to veer to the left, then departed the left side of the runway and ground looped. The airplane struck a runway sign located approximately 30 ft from the runway, and the fuselage sustained substantial damage. The pilot reported that there were no preaccident mechanical malfunctions or failures that would have precluded normal operation.