On July 30, 1996, about 1330 Alaska daylight time, a wheel equipped Cessna 180 airplane, N1746C, sustained substantial damage during an off airport precautionary landing. The precautionary landing occurred in the north end of the Chitistone Pass, located about 25 miles northeast of Mc Carthy, Alaska. The accident site elevation was approximately 5,600 feet. The solo commercial certificated pilot was not injured. The 14 CFR Part 91 flight operated in instrument meteorological conditions. A company flight plan was in effect at the time of the accident. During a telephone conversation with the NTSB investigator-in-charge (IIC) on August 1, the air taxi pilot related that the accident flight was his third flight of the day through the Chitistone Pass. He said on the accident flight, he was flying a company airplane for personal use. He said as he flew through the pass, the weather conditions were "marginal VFR", and continued to deteriorate as he flew northward. As he neared the north end of the pass, he realized he could not see the valley beyond the end of the pass. He said he turned the airplane around and tried to fly to the south, but the weather had closed in all around. He made "a quick decision" to perform a precautionary landing on the tundra. The airplane's main landing gear was torn from the fuselage during the landing.