On February 16, 2005, about 1500 Alaska standard time, a ski-equipped Piper PA-18 airplane, N9071D, sustained substantial damage when it nosed over during an emergency landing on a snow-covered, frozen lake, after a main landing gear ski was damaged during the takeoff roll on the same lake. The remote lake is about 15 miles north-northeast of Talkeetna, Alaska. The airplane was being operated as a visual flight rules (VFR) cross-country personal flight under Title 14, CFR Part 91, when the accident occurred. The airplane was operated by the pilot. The commercial certificated pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight was intended to return to Talkeetna, and no flight plan was filed, nor was one required. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on February 16, the pilot reported that he was departing a frozen lake, covered by about one-and-a-half feet of snow. The pilot said the lake is about 1/4 mile long, and he was taking off toward the east. During the takeoff run, as the airplane was about to lift off, the left ski struck a bump, or unseen object of some kind in the snow. The left ski tip rotated downward, to a near vertical position, and the pilot indicated that the ski tip retaining cable and bungee were dangling loose. The pilot made an emergency landing on the lake, and during the touchdown, the tip of the left ski dug into the snow. The airplane nosed over and received substantial damage to the wings, fuselage, and empennage.