On June 21, 1999, about 0948 Alaska daylight time, a tundra tire equipped Cessna 180 airplane, N2958K, sustained substantial damage during takeoff from an off-airport site located about 51 miles northeast of Kotzebue, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. The Swiss foreign national pilot, who holds a Swiss airline transport certificate, and the one passenger aboard, were not injured. Visual meteorological conditions prevailed, and a VFR flight plan was filed. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 21, the pilot reported that he was attempting a southeasterly departure from a 1,700 feet long off-airport site. He stated that during the early stages of the takeoff roll, the airplane veered to the left. He said that he applied full right rudder in an attempt to correct, but the airplane continued off the left side of the site, pivoted 90 degrees to the left, and nosed over. He stated that the airplane sustained substantial damage to the fuselage, wings, and lift struts. The pilot reported that the airplane had recently been retrofitted with oversized tundra tires. He added that there were no preaccident mechanical anomalies with the airplane. Wind conditions at the time of the accident were reported to be from the southeast, at 10 knots.