On April 6, 2007, at 1700 Pacific daylight time, a Cessna 172, N8340B, was destroyed by fire while standing during engine start at Chiriaco Summit Airport, Chiriaco Summit, California. The private pilot and passenger were not injured. The pilot, who was also the registered owner of the airplane, was operating it under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was initiating when the accident occurred, and was destined for Jacqueline Cochran Regional Airport, Thermal, California. The pilot reported that he and a passenger were preparing to depart for the return flight home. He applied primer and began to start the engine. The pilot heard a backfire and flames emitted from the engine. He continued the engine start attempt. When the flames became too excessive, the pilot and passenger exited the airplane. By the time fire department personnel arrived, the fire had destroyed the airplane. The Federal Aviation Administration accident coordinator examined the wreckage on April 28, 2007. The entire aircraft was consumed by fire. A large concentration of fire damage to the engine area was near the air inlet to the carburetor. The carburetor was disassembled and no abnormalities were noted.