On December 28, 2002, at 1450 mountain standard time, a Beech F33A, N1592W, piloted by a private pilot, sustained substantial damage during a wheels up landing at the Durango/La Plata County Airport (DRO), Durango, Colorado. Visual meteorological conditions prevailed at the time of the accident. The personal, cross-country flight from Borger, Texas, to Durango, Colorado, was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot and two passengers on board the airplane reported no injuries. The flight originated at 1320 central standard time. In his written statement, the pilot said he made a crosswind approach for runway 02. He said he entered a gradual climb to slow his airplane down enough to lower the landing gear, and then hit the gear switch thinking he had engaged it. The pilot said he turned downwind until the other traffic was clear, and then turned subsequently on to base and final. The pilot said on final he lowered full flaps. He said he did not realize there was a problem until he struck the runway. The pilot said the airplane is equipped with a landing gear warning horn that goes off when the airplane slows sufficiently and the gear is not down. He said the horn did not go off. An examination of the airplane showed the bottom fuselage skin beneath the cabin area and the nose gear doors scraped aft longitudinally. The bottom fuselage skin between the wing roots, beginning at the leading edges and running rearward to the trailing edges of the flaps, was buckled and pushed upward slightly. The lower portions of the bulkheads in this area were buckled. The inboard trailing edges of the left and right flaps were split open, bent, and buckled. Both propeller blades were bent aft and curled at the tips, and showed torsional bending and chordwise scrapes. The airplane's landing gear was confirmed in the up and locked position. Flight control continuity was confirmed. An examination of the airplane's engine, engine controls, and other systems revealed no anomalies. The Normal Procedures Section of the Beechcraft F33A Pilot's Operating Handbook, under "Before Landing" states in item 4, "Landing Gear - Down and Check. (Observe maximum extension speed)" The Systems Description Section of the Pilot's Operating Handbook, under "Warning Horn" states, "With the landing gear retracted, if the throttle is retarded below approximately 12 in. Hg (inches-Mercury) manifold pressure, a warning horn will sound intermittently."