On June 26, 1997, at 1944 mountain daylight time, a Cessna 210, N9417T, registered to Arrow Aviation, Inc., d/b/a MedArrow, was substantially damaged when the main landing gear collapsed during landing at Peyton, Colorado. The commercial rated flight instructor and private pilot receiving instruction were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the instructional flight being conducted under Title 14 CFR Part 91. The flight originated at Colorado Springs, Colorado, approximately 1820. According to the flight instructor, the private pilot was receiving a biennial flight review (BFR) and an aircraft rental checkout. After performing maneuvers in the local practice area, they proceeded to Meadowlake Airport to perform touch and go landings. The private pilot's first landing attempt was aborted and he executed a go around. On the downwind leg, both pilots went through the GUMPs (Gas, Undercarriage, Mixture, Prop) check list, and the landing gear was extended. Looking outside, both pilots confirmed the landing gear was extended, it was visible in the mirrors, the landing gear control had returned to the neutral position, and the green (gear down and locked) light illuminated. When the airplane was turned onto final approach, both pilots again confirmed the landing gear was down and locked. The airplane landed with the nose gear extended and the main landing gear down but unlocked. The empennage dragged along the runway, damaging both horizontal stabilizers and elevators. As the airplane slowed, it veered left and the right horizontal stabilizer struck a taxiway sign. A mechanic at the airport witnessed the accident and said the main landing gear was trailing as the airplane made its landing approach. The instructor said N9417T had "a long history of (landing) gear problems ranging from accidents where the pilot failed to extend the landing gear, to occurrences where the pilot had visually confirmed the landing gear in the down and locked position prior to touchdown and the main gear failed to remain down and locked." He said there had been "a total of five gear related incidents" with the airplane, the latest occurring in February 1997. According to the operator, he went to the accident site and examined the airplane. In a written statement, he said he found the landing gear control in the down position and not in the neutral position. When the master switch was turned on, the gear safe light did not illuminate. When the airplane was lifted, the main landing gear dropped freely and locked in the down position. The gear safe light then illuminated. The operator also disputed the pilot's claim that the airplane had been involved in five previous landing gear incidents. He said there had been only two prior accidents. According to the CESSNA 210 OWNER'S HANDBOOK, the procedure for lowering the landing gear is for the pilot to pull the landing gear control out and over a "gate" to the down position. The system incorporates positive mechanical up and down locks operated by separate hydraulic actuators, and limit switches wired in series so that all three gears must be down and locked before the indicator light illuminates. If the landing gear is not down and locked and the throttle is retarded (as in a landing approach), a gear unsafe warning horn will sound. The instructor said the horn never sounded. FAA's principal maintenance inspector for Arrow Aviation conducted an unannounced inspection of the company's maintenance facility following this accident. He reported all records were in order and procedures were being followed according to applicable regulations. Examination of N9417T revealed the landing gear had been properly rigged. The operator reported that when the airplane was placed on jacks, functional testing of the landing gear disclosed no anomalies.