Incident Overview
During the landing roll, the pilot reported a noticeable decrease in brake effectiveness. As the end of the runway became visible, the pilot attempted to execute a ground loop to avoid overrunning the runway, but was unable to establish a significant rate of turn. The aircraft subsequently departed the runway at an angle of approximately 25 degrees from the runway heading, entered a ditch, and nosed over.
Brake System Examination
Post-incident examination of the brake system revealed that the right brake cylinder showed evidence of fluid leakage around the shaft. The brake system was serviced with approximately four ounces of fluid, after which full braking action was restored. Additionally, the brake pads were found to be worn to half their original thickness. These pads had been replaced 34.5 flight hours prior to the incident.
Conclusion
The pilot's report and subsequent examination indicate a loss of braking effectiveness due to a leaking brake cylinder and worn brake pads, which contributed to the runway excursion and nose-over. The aircraft sustained damage during the event.