On January 30, 2006, about 1130 Pacific standard time, a Cessna A185E, N2303Y, sustained substantial damage when the left main landing gear collapsed during landing at a private airstrip approximately 25 nautical miles south southeast of Lewiston, Idaho. The private pilot and the two passengers aboard were not injured. The airplane was registered to the Bentz Fence Company Inc. of Lewiston and operated by the pilot. Visual meteorological conditions prevailed and no flight plan was filed for the 14 CFR Part 91 personal flight that departed from the Lewiston - Nez Perce County Airport about 1100 with an intended destination of the private airstrip. According to the pilot, upon touchdown, the left landing gear leg "started to fail" as the airplane's weight came onto the wheels. The left gear folded outward, and the airplane veered to the left. The airplane's left wing tip contacted an embankment, and the airplane came to a stop. Examination of the airplane by an FAA inspector revealed that there was structural damage to the left gear box, left wing strut, left wing tip, left aileron, the rear spar of the left wing, and the propeller. The inspector found that the 7/16-inch AN bolt that held the left gear leg to the fuselage failed in shear loading. Failure of the bolt allowed the gear to pivot on the landing gear box leading to failure of the lower landing gear box web.