On October 15, 1999, at 1650 central daylight time, a Cessna 172G, N4621L, owned and piloted by a commercial pilot, was substantially damaged following a loss of directional control during landing on runway 34 (3,200 feet by 75 feet, asphalt) at Cambridge Municipal Airport, Cambridge, Minnesota. The right main landing gear strut had fractured at a weld attaching the cabin entry step to the strut. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was not operating on a flight plan. The flight departed from Anoka County Airport, Blaine, Minnesota, at 1445, en route to Cambridge Municipal Airport. The pilot reported the following in a written statement, "...Upon touchdown on runway 34, I heard a loud snapping noise and then felt something hit bottom right side of fuselage and aircraft began to swerve to right side of runway. I immediately pulled throttle and mixture out and applied left brake to try to return to centerline. The aircraft continued to track off runway into a grassy area on east side of runway. The aircraft stopped approximately 25 yards from edge of runway 34 with the right wingtip and right elevator touching the ground. The right main spring steel landing gear was found at edge of runway." Inspection of the right main landing gear by a Federal Aviation Administration Maintenance Inspector revealed that the cabin entry step was welded on the bottom side of the strut. The cabin entry step on the left main landing gear strut was also welded to its strut. According to the FAA Inspector, there was no logbook entry regarding the welding of the cabin entry step. The last annual inspection was not performed by an inspection authorized (IA) airframe and powerplant mechanic. The Cessna Service Manual states the following under section 5-7, Step Bracket Replacement, "The step bracket is secured to the landing gear strut with Conley-Weld, or a similar epoxy base adhesive."