On August 21, 1999, approximately 2020 mountain daylight time, a Cessna 180, N1630C, registered to and operated by the pilot, was substantially damaged when it collided with terrain during landing at Heber Valley-Russ McDonald Field, Heber City, Utah. The private pilot, the sole occupant aboard, was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the business flight being conducted under Title 14 CFR Part 91. The flight originated at Fullerton, California, at 1220 Pacific daylight time. According to the pilot, "dusk seemed to set in quickly and visibility to the north was reducing rapidly." He decided not to continue further but land instead at Heber Valley Airport. He determined the winds were calm and was advised by another pilot that runway 21 was the active runway. He made a three point landing. As brakes were applied, the airplane veered to the right, the left wing struck the runway, and the airplane ground looped. According to the airport manager, a stain, similar to brake fluid, was found on the runway and led to where the airplane came to a halt. An FAA airworthiness inspector examined the airplane and reported that the left brake line separated from the caliper assembly, stripping the threads. There was no loop, or slack, in the brake line. The airplane had brake work done a year before the accident.