On September 17, 2003, about 1935 Pacific daylight time, a Cessna 172S, N3555L, sustained substantial damage during a taxiway overrun at the Anacortes Airport, Anacortes, Washington. The airplane is registered to Rugby Aviation of East Sound, Washington, and was being piloted by the private pilot as a visual flight rules (VFR) cross-county flight under the provisions of 14 CFR Part 91. The pilot, and the one passenger aboard the airplane were not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the proposed flight to East Sound, Washington. During a telephone conversation with the National Transportation Safety Board IIC on November 3, the pilot reported he experienced a complete wheel brake failure while taxiing for takeoff. The pilot said that he applied brakes, with little response, as the airplane neared the end of the inclined taxiway. He reported that he was not able to stop the airplane, and it continued off the end of the taxiway. After exiting the taxiway, the airplane encountered rough uneven terrain and eventually came to rest, nose down, in a drainage ditch. In a written report dated November 3, 2004, the pilot stated that on the previous landing, the airplane "shuttered violently" when he applied wheel brakes during the landing roll. He stated that after parking the airplane he noticed brake fluid "dripping" from the area of the wheel brakes. In the written report, the pilot states that after discovering the problem with the brakes, he contacted the operator of the airplane. According to his report, the operator instructed the pilot to "...ferry the aircraft back to ORS [Orcas Island] for maintenance." In a written report dated November 20, 2003, the operator stated that the pilot advised him that only a small amount of brake fluid had leaked from the system. Post accident examination of the wheel brake components by an investigator from the National Transportation Safety Board revealed that the brake pads were worn beyond limits, which allowed the caliper seals (O-ring) to unseat resulting in a loss of brake fluid.