On February 27, 1999, at 0800 eastern standard time, a Gulfstream American AA-5B, N4524Y, was substantially damaged during a forced landing on final approach to the Sanford Regional Airport (SFM), Sanford, Maine. The certificated private pilot and pilot-rated passenger were not injured. Visual meteorological conditions prevailed for the personal flight that originated at Hillsboro, New Hampshire (8B1), approximately 0735. No flight plan was filed for the flight conducted under 14 CFR Part 91. In telephone interviews, the pilot stated the purpose of the flight was to demonstrate the airplane to the passenger who was interested in purchasing a similar make and model. The pilot said he drained fuel from the sumps during the preflight inspection and that the fuel was absent of contamination. He said he did not visually check the fuel quantity in the tanks. The pilot said he had flown approximately 1 hour since the last fuel service, which completely filled the tanks. He said, "Both gauges were reading almost full." The pilot said the flight from 8B1 to SFM was approximately 25 minutes and he entered the traffic pattern for landing. He said he extended the downwind leg to allow for traffic landing ahead of him. The pilot said, "When I entered the downwind leg, I applied carb heat, mixture full rich, and fuel pump on. I'll come in around 1500 RPM and watch my speed. I try to get it down to 60 knots because the Tiger's hard to slow down. Turning final on runway 34, the engine started losing RPM. At about 600 feet I lost power and did a forced landing. I stalled it into a tree." The chief of the Sanford Fire Department responded to the scene. He said the airplane was suspended in a tree. He said, "The nose was straight down in the trees. The fuel was dripping from the right wing, whether it was running from the left side and dripping from the right, I can't tell you." The airplane was recovered from the tree by helicopter. Examination of the airplane by a Federal Aviation Administration (FAA) Airworthiness Inspector revealed the left fuel tank was compromised during the accident sequence. The right fuel tank was intact and contained no fuel. On March 4, 1999, the airplane's engine started and ran on the airframe utilizing the airplane's own fuel system. According to the FAA Inspector, the engine ran "rich" and continued to run after the mixture control lever was moved to the Idle Cut-off position. In a subsequent telephone conversation, the pilot said that a review of his records revealed the airplane had flown approximately 2-2.5 hours since the last fuel service. The pilot estimated his fuel burn rate averaged 10 gallons per hour. He said he adjusted the fuel mixture in flight based on exhaust gas temperature (EGT) and cylinder head temperature (CHT) readings. He said, "I watch EGT and CHT. They're both on a digital gauge." The AA-5B had a fuel capacity of 26 gallons per wing tank for a total of 52 gallons. The pilot was asked if he noted any deficiencies in the performance or flight characteristics of the airplane. He responded, "I've had no problems ever. Never." The pilot reported 1,973 hours of total flight experience, 156 hours of which were in make and model.