What happened
During an approach to land to the south under visual meteorological conditions with light and variable winds, the pilot experienced a sudden swerve to the right. In an attempt to correct the deviation, the pilot overcorrected, resulting in a ground loop to the right.
The force of the maneuver caused the right main landing gear to collapse. As the aircraft moved, the right wing struck the ground, which resulted in a bent rear spar. The pilot was not injured during the event.
Findings
In a written statement, the pilot acknowledged that the aircraft had landed with excessive speed and had not reached a complete stall prior to touchdown. The pilot also noted that back pressure on the elevator had been relaxed and the tailwheel had not been properly planted.
The pilot identified fatigue as a primary factor, noting that he had been working the graveyard shift for the previous seven nights and was very tired at the time of the flight.