On January 12, 1998, at 1210 eastern standard time, a ski equipped Cessna 150J, N51258, sustained substantial damage during a hard landing on a snow covered, frozen lake near Gaylord, Michigan. The main landing gear utilized an extension to relocate the axle. That extension fractured and the airplane ground looped. The pilot reported no injuries. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions. No flight plan was on file for the local flight which departed from the Otsego County Airport also near Gaylord, about 1100. The pilot stated that the right main landing gear extension failed after three landings and on taxi to his hangar. He said that the substantial damage to the airplane occurred at that time. A witness who talked to the police made a written statement indicating that she watched the airplane make three separate landings and that on the last landing, "Just before it touched down, it kind of hovered sideways and then went almost straight down, bounced back up once and back down and slowly tipped over onto the nose, and one wing." The fractured landing gear extension was examined by the NTSB's Office of Research and Engineering. Their report No. 98-127 is attached as an addendum to this report. The report indicated that the, "... fracture surfaces showed a majority of fracture features consistent with a failure in overstress." The report indicated that there was a uniformly blackened area on the edge of the surface located at the side of the radius of a cut-out. The blackened area was cleaned and found to be corroded. The corrosion was found in a pattern which appeared to coincide with the outline of the main landing gear leg.