On October 12, 2023, about 0250 mountain daylight time, a Cessna 340A airplane, N682JS, was substantially damaged when it was involved in an accident at Boise Air Terminal/Gowen Field, (BOI) Boise, Idaho. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 repositioning flight. The pilot reported that, while taxiing for departure, the right brake failed while he was attempting to stop the airplane. The airplane veered left and subsequently impacted the airport perimeter fence, resulting in a fire when the left wingtip fuel tank was breached. Examination of the airplane’s brake system revealed continuity to each wheel brake and appropriate servicing of the brakes’ cylinders. The brakes were cycled, activated, and released appropriately. The wheels and tires were examined, and no anomalies were noted. Examination of the nose wheel steering system was accomplished by jacking up the nose wheel and verifying proper nosewheel and rudder deflection. There was no evidence of a failure or malfunction that would have precluded normal operation of the airplane. A review of airport surveillance video captured the airplane taxiing and the impact with the fence. In the seconds before impact, the airplane did not noticeably slow down or change direction. The video indicated that the airplane was traveling the same direction and gradually drifted to the left until the wingtip tank made contact with the fence and the airplane pivoted around the left wingtip, which became embedded in the fence. There was a tire skid mark right of the taxi throughway that was offset about the distance of the airplane’s right main landing gear tire. The black skid mark was narrow and veered to the left across the centerline and into the area of the fence impact, consistent with the airplane’s right main tire being side-loaded and not locked. No other tire skid markings were noted in the area.