On September 6, 2003, at 0801 mountain daylight time, a Cessna 150J, N60571, operated by the pilot, was substantially damaged when it impacted terrain during a forced landing at Four Corners Regional Airport (FMN), Farmington, New Mexico. The private pilot, the sole occupant on board, received serious injuries. Visual meteorological conditions prevailed. No flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated at Aztec, New Mexico, at approximately 0740. According to the tower operator at FMN, as the airplane was entering a left base for runway 07, an expletive was heard over the tower frequency and shortly thereafter an emergency locator transmitter (ELT) signal was heard. When emergency personnel arrived at the site, they found the pilot had already pulled himself out of the inverted airplane and was sitting on the wing. Concerned about a possible fuel leak, they asked the pilot if he knew how much fuel was in the [fuel] tanks. The pilot said "we probably don't have to worry about a fuel leak." Although no fuel leak was noted, approximately 9 gallons of fuel was recovered from the fuel tanks. The pilot stated that he entered left downwind and was preparing for a touch-and-go landing on runway 07. He said he did not pull the carburetor heat on until after the turn to final. At that point, the engine "suffered a loss of power" but, it did not "miss or sputter." As the airplane descended below runway elevation, he attempted to land in the only available clear area. The airplane impacted the terrain on the landing gear. When the nose landing gear collapsed, the airplane nosed over and slid approximately 50 feet. The engine was separated from the fuselage, the top of the vertical stabilizer was crushed, and the empennage was buckled. At 0816, the recorded weather conditions at FMN was: wind, 090 degrees at 9 knots; visibility, 10 statute miles; sky condition, clear; temperature, 16 degrees C.; dew point, 11 degrees C.; altimeter setting, 30.22. The calculated density altitude was 6,642 feet msl. According to carburetor icing charts, the weather conditions were conducive for "serious" carburetor icing at any power setting. According to the Cessna 150 pilot's operating handbook (POH), on the "Normal Procedures Checklist" under "Before Landing," item (2) Carburetor Heat, states, "Apply full heat before closing throttle."