Incident Details
On August 23, 2022, at approximately 0930 Pacific daylight time, a Champion 7GCBA airplane, registration N9512S, was substantially damaged in an accident near Athol, Idaho. The aircraft was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot and passenger were not injured.
Pilot Account
The pilot reported that the first flight of the day in the tailwheel airplane was uneventful. The second flight, which was the accident flight, was also uneventful from takeoff until touchdown. During the landing roll, the right brake became inoperative, causing the airplane to veer to the left and depart the runway surface into a ditch. Subsequently, the right main landing gear collapsed, resulting in the right wing impacting terrain.
Postaccident Examination
Postaccident examination by a Federal Aviation Administration inspector revealed that the right brake master cylinder piston rod had become disconnected from the right rudder pedal assembly. The cotter pin that should have secured the clevis pin was missing. The clevis pin was found located under the right-side floorboard. Minor wear and markings on the clevis pin's cadmium plating were consistent with the pin having been installed; no wear or markings were observed in the cotter pin hole. The missing cotter pin was not located. The left pedal assembly was properly connected with a cotter pin.
Maintenance History
The airplane had undergone a conversion to a hydraulic toe brake rudder assembly in October 2019. According to the pilot, the airplane had flown approximately 12 hours since the conversion. The airplane's annual inspection was completed 12 days and about 1.3 hours (tachometer time) before the accident. The mechanic who performed the inspection stated that he inspected the right brake system but did not recall or notice whether a cotter pin was installed in the clevis pin. He further stated that if he had noticed a missing or damaged cotter pin, he would have replaced it.