Right Brake Failure Leads to Ground Loop and Gear Collapse (N80124)

What happened

The pilot reported experiencing a loss of hydraulic pressure to the right brake system prior to initiating the landing flare. Upon touchdown on the runway, the aircraft's tailwheel began to shimmy violently. This mechanical oscillation caused the nose to yaw sharply to the left. The pilot applied full right rudder input in an attempt to maintain directional control and counteract the pull. Despite these efforts, the aircraft continued to turn left uncontrollably, resulting in a ground loop. Following the loss of control on the ground, the right main landing gear collapsed under the stress of the maneuver.

The investigation

Post-acc examination confirmed that the right brake system had no pressure prior to the landing roll. The tailwheel assembly exhibited signs of shimmy during the initial phase of the ground roll. The right main landing gear structure sustained significant damage consistent with a collapse following the ground loop event.