NTSB Identification: GAA18CA209
According to the flight instructor in the tailwheel-equipped airplane, the pilot receiving instruction was on the flight controls during the landing roll. Near the end of the roll the tail began to swerve, and the airplane ground looped to the right. The airplane exited the right side of the runway and the left wing struck the ground.
The airplane sustained substantial damage to the left-wing spar and aileron.
The pilots reported that there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation.