On June 24, 2000, at 1130 central daylight time, a Piper PA-28-161 single-engine airplane, N8427K, collapsed the left main landing gear during the landing at the McKinney Municipal Airport, near McKinney, Texas. The airplane was owned by Victor Players, Inc. and operated by Classic Aviation of Addison, Texas. The flight instructor and the student pilot were not injured, and the airplane sustained substantial damage. Visual meteorological conditions prevailed for the cross-country instructional flight under 14 Code of Federal Regulations Part 91, and a flight plan was not filed. The flight departed the Addison Airport, Addison, Texas, at 1030. The flight instructor reported that the student pilot initiated the landing on runway 17, and during the landing roll approximately 45 knots, the airplane veered left. The flight instructor took the airplane controls and applied right rudder; however, the airplane continued to the left and exited the runway. The left main landing gear collapsed, the left wing struck the ground, and the airplane came to rest. Examination of the airplane, by the FAA inspectors and the operator, revealed that the top attachment bolts for the left main landing gear had sheared. The operator reported that the airplane had accumulated 11,500 hours of total flight time during its utilization at the flight school. The operator reported structural damage on the left wing and a "stress crease on the left horizontal stabilizer." On June 30, 2000, under the supervision of the FAA inspector, the left main landing gear strut assembly was examined at Air Salvage of Dallas, Lancaster, Texas, by the manufacturer's representative. The lower end of the strut housing/cylinder (P/N 65319-04) was found separated. The separation area was "symmetrical with no evidence of corrosion or pre existing damage noted." Examination of the inside of the cylinder found "impact marks around the forward side of the cylinder in the area where the top of the inner strut tube would normally be when it's near the extended position." The "damage was consistent with landing gear impacting a solid object (edge of runway, hole, etc.) at a time when there was little or no weight on the landing gear and the strut was near full extension." The attachment bolts "appeared to have separated cleanly from excessive shear force and did not appear to be a factor in the occurrence."