What happened
The pilot departed for a flight intended to perform touch-and-go landings. After approximately 30 minutes of uneventful flight, the aircraft entered a right traffic pattern for runway 18 under light and variable wind conditions. During the initial rollout on final approach, the pilot noticed the aircraft drifting to the right despite winds being nearly aligned with the runway. The pilot observed a sensation of skidding, which was confirmed by the turn and bank indicator showing the ball fully deflected to the left, even without right rudder input.
In response to this instability, the pilot transitioned from touch-and-go landings to full-stop landing attempts. A go-around was performed, followed by a second go-around after the second approach proved similarly uncomfortable. During a third approach, the pilot applied full left rudder and nearly full left aileron inputs to maintain wings level and a straight path down the runway, noting that left rudder input appeared ineffective. After a momentary wheel landing, the tailwheel contacted the runway, at which point the aircraft swerved violently to the right. The Cessna (type not specified in source, but context implies light aircraft) departed the runway into the grass and underwent a ground loop, coming to rest with the empennage elevated. There were no injuries reported.
The investigation
An examination of the rudder flight control system revealed that the left rudder cable had come off the pulley, and a light hand pull on the cable allowed for lateral deflection of one to two inches. While the rudder control surface and tailwheel were free to move without binding, and neither rudder return spring nor the cables had failed, the cable displacement was identified.
Maintenance records showed the aircraft had undergone an annual inspection on November 24, 2001, with approximately 22 hours flown since that inspection. Records indicated a restoration period between December 1991 and May 1995, but no work had been performed on the rudder flight control system in the preceding five years. The service manual notes that rudder cable tension is specifically checked during 100-hour, 500-hour, and 1,000-hour inspections.