On March 23, 1996, at 1000 Alaska standard time, a wheel equipped Piper PA-12 airplane, N2431M, registered to and operated by the student pilot, experienced a power loss and subsequent forced landing near Cantwell, Alaska. The student pilot, on his first solo cross country flight, was operating under 14 CFR Part 91. No flight plan was filed and visual meteorological conditions prevailed. The flight departed Merrill Field, Anchorage, Alaska, and the destination was Cantwell. The airplane received substantial damage and the student pilot, the sole occupant, was not injured. During a telephone conversation with the student pilot on March 23, 1996, he stated that he had overflown the Summit airport to view the conditions of the runway prior to landing. The runway was unsuitable for landing and as he passed the runway the engine began to lose power. He was unable to turn toward the runway and elected to land near a road. The pilot landed the airplane in deep snow and the airplane struck a snow bank. Examination of the airplane and engine was accomplished by Ernie's Aircraft Service of Anchorage, Alaska. The examination determined the following: 1. The engine turned freely and was lubricated. 2. The magnetos were timed correctly and the "P" leads were not grounded. 3. The fuel flowed to the carburetor. 4. The carburetor air box was clear of obstructions. 5. The airplane was not equipped with a header tank. 6. The fuel quantity could not be determined because the wings had been removed and the fuel drained. Ernie's Aircraft could not find any mechanical problems with the engine. During the interview with the pilot on March 23, 1996, he stated that he had fueled the airplane the previous day with 19 gallons of fuel. He then flew the airplane approximately 1 hour. He did not refuel the airplane prior to this flight. He stated that the airplane carries 5 hours of fuel on board. He had flown approximately 2.0 hours during this flight. During the pilot interview he stated that he had applied carburetor heat before reducing the engine power. There are no weather reporting facilities at the accident site and the temperature and dewpoint spread are undeterminable. During the initial interview with the student pilot, he stated that the engine windmilled for a short time until he slowed his airspeed. At that point, the propeller stopped windmilling. During a subsequent conversation with the student pilot, he stated that his instructor told him if the propeller stopped windmilling it was a mechanical failure.