ANC04LA005

The commercial pilot was flying over mountainous terrain when he noted a rough running engine and a slight reduction in engine rpm. He applied full carburetor heat, which was followed by a rapid loss of engine power, and subsequent loss of altitude. Unable to restore adequate engine power to maintain level flight, the pilot selected an uphill portion of a mountainside as a forced landing site. During touchdown on the soft, tundra-covered terrain, the left main landing gear collapsed, and the left wing struck the ground. The airplane sustained structural damage to the left wing and fuselage. The pilot said that weather conditions at the time of the accident were, in part: Visibility, 10 statute miles in light rain and mist; clouds and sky condition, 3,000 feet overcast; temperature, 40 degrees F. The pilot reported that there were no preaccident mechanical anomalies with the airplane, and that the loss of engine power was due to carburetor icing.

On November 2, 2003, about 1700 Alaska daylight time, a tundra tire-equipped Piper PA-20 airplane, N1486A, sustained substantial damage when the left main landing gear collapsed during a forced landing following a loss of engine power, about 65 miles east of Bethel, 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 commercial certificated pilot sustained minor injuries, and the sole passenger aboard was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated about 1545, from the Aniak Airport, Aniak, Alaska, and was returning to Aniak when the accident occurred.

During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on November 5, the pilot related that the purpose of the flight was to view some Alaskan scenery, and added that two off airport landings were accomplished prior to the accident. He said that on the return flight to Aniak, while over mountainous terrain, he noted a rough running engine and a slight reduction in engine rpm. He applied full carburetor heat, which was followed by a rapid loss of engine power, and subsequent loss of altitude. The pilot said that he was unable to restore adequate engine power to maintain level flight, and he selected an uphill portion of a mountainside as a forced landing site. During touch down on the soft tundra-covered terrain, the left main landing gear collapsed, and the left wing struck the ground. The airplane sustained structural damage to the left wing and fuselage.

The pilot reported that weather conditions at the time of the accident were, in part: Visibility, 10 statute miles in light rain and mist; clouds and sky condition, 3,000 feet overcast; temperature, 40 degrees F.

The pilot reported that there were no preaccident mechanical anomalies with the airplane, and that the loss of engine power was due to carburetor icing. According to the pilot, Piper PA-20 airplanes with Lycoming O-290-D engines are highly susceptible to carburetor icing.