Incident Details
A pilot experienced a vibration during a landing at a local airport, which he believed originated in the tailwheel. In response, the pilot and a mechanic tightened the tailwheel nut. After this corrective action, the pilot elected to proceed to his next destination.
Sequence of Events
During the subsequent landing at that destination, the vibration recurred. As the airplane continued its landing roll, it veered off the runway and executed a ground loop. The pilot had reported the previous vibration and the tightening of the tailwheel nut prior to the accident flight.
Post-Accident Examination
An examination of the tailwheel following the accident revealed no anomalies. No other mechanical issues were documented. The investigation did not determine a root cause for the vibration or the loss of directional control.