On December 16, 1999, at 1501 mountain standard time, a Beech N-35, N9468Y, made a forced landing approximately 2 miles short of runway 28 at Centennial Airport, Englewood, Colorado, following a complete loss of power. The airline transport pilot and his passenger were not injured; however, the aircraft sustained substantial damage. Visual meteorological conditions prevailed for this personal flight conducted under Title 14 CFR Part 91 and a VFR flight plan was filed. The flight originated from North Platte, Nebraska, at 1300. According to the attached pilot narrative, he was in communication with Centennial tower and reported a 3-mile final as instructed. The flight was cleared to land on runway 28. At 2 miles from the runway at about 800 feet above ground level, the pilot said he "switched the fuel selector to the right tank (fullest), rechecked the landing gear down, advanced the mixture slightly toward rich (go-around preparation), and checked the prop to full rpm. Flaps were selected visually to one quarter." The pilot said the engine began to lose power and he advanced the throttle. The power loss continued and he said he retarded the mixture towards lean without effect. He stated he tried different combinations of mixture, throttle, and boost pump but did not regain power. In the ensuing forced landing, the aircraft impacted in a ravine and came to rest 300 feet from the initial impact point on the side of a hill. During the forced landing, the propeller was damaged, the nose landing gear collapsed and the lower forward fuselage was displaced upward into the cabin and engine compartment. In addition, both wings suffered spar and skin damage. On February 11, 2000, after installing a test propeller and cutting off the tips of the exhaust stacks which had been crushed during the forced landing, the engine was run mounted on the airframe and using the normal fuel feed system. The engine performed in a normal fashion throughout the designed power range. During the investigation, interviews were conducted with persons from Rocky Mountain Straight Flight, the company that retrieved the aircraft, and with the insurance adjuster who processed the accident claim. Both provided information that the pilot stated to them that he had inadvertently shut off the fuel when he switched fuel tanks while executing the items on the checklist in preparation for landing.