On April 22, 2006, approximately 2110 mountain daylight time, a Cessna TR182, N6170S, piloted by a private pilot and accompanied by an ATP-certificated flight instructor, was substantially damaged when the landing gear was inadvertently retracted while taxiing from landing at Centennial Airport (APA), Englewood, Colorado. Visual meteorological conditions prevailed at the time of the accident. The local personal flight was being conducted under the provisions of Title 14 CFR Part 91 without a flight plan. The two pilots were not injured. The originated approximately 1930. The airplane landed at APA and, according to the pilot, he may have "possibly inadvertently hit the gear handle." The nose gear retracted and the airplane skidded down the centerline before drifting off the left side and sliding another 300 feet. The left main landing gear then retracted. In addition to a broken left wing tip fairing, scraped landing gear doors, a crushed exhaust manifold, and a bent propeller, there was structural damage to the nose wheel tunnel. According to a Cessna Aircraft Company spokesman, the airplane was equipped with a "squat switch" that senses weight-on-wheels, and prevents inadvertent landing gear retraction. The spokesman said there were several reasons why the landing gear may have retracted: a defective squat switch, an over-inflated nose gear strut (that would cause the electrical contacts of the squat switch to separate), misrigging of the squat switch, or the airplane may have bounced, allowing the electrical contacts to separate. According to the repair facility that retrieved the airplane, the squat switch was functionally tested and it operated satisfactorily.