What happened
During a flight intended to check out a pilot on the aircraft, the pilot experienced a loss of directional control while rolling out after landing. This resulted in a slow right turn that caused the airplane to exit the runway. The aircraft eventually came to a stop approximately 20 feet from the runway edge, facing in the opposite direction of its original heading.
The investigation
Upon inspection following the ground loop, it was determined that the side load applied to the tail section during the maneuver caused significant structural damage. The force ripped the tailwheel away from the empennage at its attachment points and resulted in a bent bulkhead. The pilot reported that there had been no mechanical failures or malfunctions involving any aircraft systems prior to the loss of control.