On June 28, 2001, about 1200 Alaska daylight time, a wheel-equipped Grumman G-164 airplane, N364Y, sustained substantial damage during takeoff at the Willow Airport, Willow, Alaska. The airplane was being operated as a visual flight rules (VFR) business flight under Title 14, CFR Part 91, when the accident occurred. The purpose of the flight was to deliver fuel. The airplane was registered to, and operated by, Valley Aviation LLC, Palmer, Alaska. The solo certificated commercial pilot was not injured. Visual meteorological conditions prevailed, and company VFR flight following procedures were in effect. The flight originated at the accident airport about 1155. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 28, the pilot reported that the airplane was loaded with about 300 gallons of diesel fuel. The pilot reported that while departing runway 31, about 75 feet above the runway, the engine began to lose power. He said that emergency engine procedures did not restore power. The airplane landed on the runway, about 100 feet from the runway threshold, continued off the end of the runway, and collided with a stand of trees. The airplane sustained substantial damage to the fuselage, wings, and empennage. A Federal Aviation Administration (FAA) airworthiness inspector, Anchorage Flight Standards District Office, examined the airplane at the accident scene on the accident date. He reported that the airplane came to rest in a nose down position, and the engine had been torn off in the accident. The inspector also reported that after the accident, most of 300 gallons of diesel fuel leaked out of the accident airplane's 325 gallon hopper tank. The FAA inspector, in conjunction with the accident pilot, estimated the gross weight of the accident airplane, during the accident flight, to be about 1,248 pounds over of the maximum allowable gross weight. While at the accident scene, the FAA inspector interviewed a witness to the accident. The witness reported that the accident airplane's engine appeared to be operating normally, and that the takeoff roll also seemed normal. The witness stated that as the accident airplane climbed to about 50 feet above the runway surface, the airplane stopped climbing, and eventually settled back onto the runway.