Accident Details
On July 26, 2015, at about 0830 mountain daylight time, a Cessna 180J, registration N52095, sustained substantial damage while taxiing for takeoff at the Wilson Bar USFS Airport (C48) in Dixie, Idaho. The airplane was operated by SP Aircraft under 14 CFR Part 135 as a non-scheduled passenger flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was originating at the time, with a planned destination of Boise Air Terminal/Gowen Field, Boise, Idaho.
Pilot's Report
The commercial pilot reported that the right brake failed while performing a 180-degree turn to align the airplane with the runway. To avoid elevated terrain near the runway, the pilot intentionally ground-looped the airplane. Subsequently, the right wing struck terrain. The pilot and three passengers were not injured.
Postaccident Examination
A Federal Aviation Administration inspector examined the damaged airplane and found substantial damage to the right wing and aileron. The right brake hydraulic line was observed to be cracked at a bend between the fuselage and the main landing gear leg.
Brake System Examination
The airplane is equipped with a hydraulically actuated disc brake on each wheel. Each brake is connected by a hydraulic line to a master cylinder attached to each side of the pilot's rudder pedals. The appropriate section of the brake hydraulic line was removed and sent to the National Transportation Safety Board Materials Laboratory Division for detailed examination. Electron microscope images revealed that the brake line fracture surface was consistent with a fatigue fracture, with fatigue striations and ratchet mark formations observed.