On June 15, 2002, approximately 2150 central daylight time, a Cessna P210N airplane, N4720P, was substantially damaged after the right main landing gear collapsed during landing roll at the Shreveport Downtown Airport (DTN), Shreveport, Louisiana. The private pilot and his passenger were not injured. The airplane was registered to and operated by Tower Systems Inc., of Tustin, California. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The flight departed the Shawnee Municipal Airport, Shawnee, Oklahoma, approximately 2030, and was destined for Shreveport. According to the pilot, while on approach to DTN, he lowered the landing gear, and the landing gear extended. However, the landing gear annunciator light (green), confirming the landing gear had extended and locked into position, failed to illuminate. By a visual check, the pilot confirmed the left main landing gear was extended, and the passenger confirmed the right main landing gear was extended. During a low approach over the runway, the tower controller performed a visual check of the nose landing gear, and the controller stated he was 90 percent positive the nose gear was extended. While landing on runway 32, the right main landing gear collapsed, the airplane veered to the right and came to rest upright off the right side of the runway. A local fixed based operator (FBO) aircraft mechanic, who assisted in the recovery of the airplane, reported that the right horizontal stabilizer and right elevator sustained substantial damage. The reason for the right main landing gear collapse was not determined.