On December 25, 2009, at 1148 central standard time, N9499X, a Cessna 210 single-engine airplane, went off the side of the runway at Robert Lee Airport (54F), Robert Lee, Texas, after the right main landing gear collapsed on landing. The commercial pilot and the passenger were not injured. The airplane was registered to and operated by the pilot. No flight plan was filed and visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91. The pilot reported that he had visually confirmed that the landing gear was extended and the all three gear-down lights were "in the green." After the airplane touched down on the runway, the right wing dropped, and the airplane veered off the right side of the runway onto the grass. The airplane sustained damage to the right horizontal stabilizer, elevator, and the right wing tip. The right main landing gear was found partially extended and pushed up into the wheel well. Examination of the airplane by an airframe and mechanic revealed that the left and right main landing gear were not fully engaging the landing gear. There were no obvious signs that the main landing gear system had any recent maintenance or any of the components were damaged. A review of the airframe logbooks did not reveal any recent maintenance to the A review of photographs taken at the accident site revealed large clumps of grass protruding from the runway surface.