On August 14, 2000, at 1004 central daylight time, a Cessna T210L single-engine airplane, N59287, was substantially damaged when the gear collapsed during landing at the Addison Airport near Addison, Texas. The airplane was registered to and operated by the Celtech Corporation of McKinney, Texas. The private pilot, sole occupant, was not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 business flight. The flight originated from McKinney, Texas, about 0950. According to the pilot, while on short final for runway 15, smoke flowed from under the instrument panel. He could not see or breath and declared an emergency to the Addison Air Traffic Control Tower. The pilot further reported that he tried to vent the cabin, but still could not see or breath. He placed the landing gear handle in the down position and continued with the landing. Prior to landing, the tower controller advised the pilot that the airplane's landing gear was extended but not fully down. The pilot landed the airplane, the landing gear collapsed, and the airplane came to rest on the east side of the runway. Examination of the airplane, by an FAA inspector, revealed that the horizontal stabilizer and elevator were structurally damaged. Examination of the cockpit revealed that a wire bundle under the instrument panel on the copilot's side had heat and fire damage. The fire damage was confined to the wire bundle. Additionally, the hydraulic motor circuit breaker was found popped.