On July 23, 2002, at 2115 central daylight time, a Cessna 402B, N22PB, piloted by an air transport pilot, sustained substantial damage when the left main landing gear collapsed while taxiing after landing at the Lambert - St. Louis International Airport (STL), St. Louis, Missouri. Visual meteorological conditions prevailed at the time of the accident. The flight was operating on an IFR flight plan under the provisions of 14 CFR Part 135. The pilot reported no injuries. The flight originated from the Columbia Regional Airport (COU), Columbia, Missouri at 2035. The pilot reported, "After landing, I taxied down 30R when St. Louis Tower instructed me to exit on taxiway November to the cargo ramp on tower frequency...At a speed of a brisk walk, I arrived at taxiway November. I started my [right] turn onto November when the left main landing gear gave way. I then notified tower immediately. I commenced emergency shutdown and egressed from the airplane." An inspector from the Federal Aviation Administration (FAA) viewed the site where the accident occurred. He reported, "I took photographs of the runway where the propeller had struck the runway and where the aircraft came to rest. This distance was approximately 120 ft." The FAA inspector reported the pilot stated that "he had 3 green lights and the gear was down and locked," and that the landing and taxiing normal until the landing gear collapsed. The FAA inspector examined the landing gear. He reported that the only visible damage to the left main landing gear system "appeared to be a sheared AN25-38A bolt which attached the rod end of the bellcrank to the Lower Side Brace, and the NAS464P4-26 bolt which attaches the upper portion of the bellcrank to the upper portion of the upper barrel. This bellcank is what keeps the side braces locked and over center." He reported that the right hand main landing gear was operated and it "appeared to be within rigging limits for downlock spring tension and freefall checks." He reported, "The Landing Gear indicating lights where checked, which appeared to function normal." The left landing gear was not operationally checked.