On May 20, 1999, approximately 1320 mountain daylight time, a Beech D95A, N64TA, was substantially damaged when the right main landing gear collapsed during landing roll at Centennial Airport, Englewood, Colorado. The commercial pilot, the sole occupant in the airplane, was not injured. The airplane was being operated by Enterprise Aircraft Management, Inc., of Denver, Colorado, under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local flight which originated approximately 30 minutes before the accident. No flight plan had been filed. The pilot said he was performing his third touch-and-go landing when, during the ground roll, the right main landing gear collapsed. The airplane went down on its right wing. Subsequently, the right wing was bent upwards and the right side of the fuselage was wrinkled. Postaccident examination of the right main landing gear strut, by a private metallurgist contracted by the insurance company, revealed a preexisting fatigue fracture which extended through approximately 50 percent of the strut.