On August 3, 2004, at 1745 eastern daylight time, a Piper PA-24-180, N6311P, was substantially damaged during a forced landing after departing from the Mid-State Airport (PSB), Phillipsburg, Pennsylvania. The certificated private pilot and two passengers were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. According to the pilot, the accident flight was the first flight of the day and the fuel tanks were full. After completing the warm-up and ground checks, the airplane departed from runway 34, a 5,711-foot-long, 100-foot-wide, asphalt runway. During the initial climb, about 400 feet above the ground, the engine lost partial power, and the airplane began to descend. Suspecting that carburetor icing was present, the pilot applied carburetor heat. A few seconds later, the airplane impacted the ground. The airplane came to rest about 1/4-mile from the end of the runway. The pilot additionally stated that he had experienced a similar problem with the engine losing partial power a few flights prior to the accident; however, it was an isolated event, and he attributed it to possibly being carburetor icing. A Federal Aviation Administration (FAA) inspector examined the wreckage after the accident. He observed substantial damage to both wings, and the forward fuselage. The inspector did not observe any anomalies with the flight or engine controls. The engine was test ran by the FAA inspector after the accident, with no abnormalities noted. The weather reported at the airport, at 1755, included winds from 240 degrees at 4 knots, clear skies, a temperature of 81 degrees Fahrenheit, a dew point of 75 degrees Fahrenheit, and an altimeter setting of 29.91 inches Hg. The density altitude calculated for the time of the accident was approximately 3,749 feet. A review of a FAA carburetor icing probability chart placed the reported temperature and dew point in the "serious icing at glide power" area of the chart. According to documents obtained during the investigation, a weight and balance was calculated for the flight, which estimated the aircraft weight as approximately 2,521 pounds. According to the PA-24-180 Owner's Handbook, the maximum gross weight was 2,550 pounds.