Incident Overview
The pilot of a single-engine tailwheel aircraft reported that the approach, landing flare, and touchdown were normal. During the initial ground roll, a very strong tail wheel vibration began, which "shook the plane and overrode my rudder controls." The pilot was unable to regain control, and the aircraft veered left, then ground looped in a very tight circle. Written statements from passengers were consistent with the pilot's account.
Post-Accident Examination
An FAA airworthiness inspector examined the runway and aircraft. On the runway pavement, tail wheel scrub marks were present in a high-frequency wave pattern that led to the point of the ground loop. Examination of the aircraft disclosed approximately 1/8-inch play in the tail wheel bearings. Additionally, the inspector reported that the tail wheel was improperly shimmed.
Maintenance History
Review of maintenance records revealed that the tail wheel had been replaced 12 days before the accident. Work orders from the repair shop that installed the unit noted that the tail wheel assembly was supplied by the owner. The work order also indicated that the bearings were replaced by the shop at the time of installation.