20000122039509A

(-23) A/c arrived at stockton air show with rough engine. Maintenance at wolf aviation, stockton, CA. Showed broken valve. Engine was overhauled by owner at that time. First flight after overhaul was accident flight. A/c was topped off with fuel after the airshow (32 gallons). Pilot said the a/c fuel burn when leaned is between 16 and 14 gph. The maintenance records indicate that ,after overhaul, the engine was run in for 2.5 hours. No record of refueling before flight. (The pilot said that he brought gas cans out and topped off the a/c). During takeoff after the overhaul (the accident lfight) a witness said that the airplane was running so poorly, the witness thought the a/c would not make it off the ground. When it did become airborn it was still running bad but did not come back to the field. Pilot made an emergency landing in a field approx. 25 NM from stockton airport. The recovery crew said that they took 5 gal out of right tank and the left tank was empty with selector in the left position. The engine ran during the engine inspection w/ntsb. (.4) the pilot made a forced landing in a plowed field following a loss of engine power. The airplane was a 3/4 scale P-51 replica with a fuel injected automotive engine. The flight departed stockton with full fuel onboard, which was 32 gallons of fuel in two 16-gallon tanks, and the engine burned about 14 gallons per hour. While cruising at 3,500 feet, the airplane gradually began to lose speed and altitude. The manifold pressure remained at a cruise setting, but the pilot felt the engine was not producing power. He switched fuel tanks from left to right, cycled the ignition switch, and adjusted the mixture. The engine coolant and oil temperature gauges remained in the green, but the power continued to decline. The pilot attempted to land in a plowed field with the landing gear down, but the landing gear separated from the airplane and damaged the wing spar. The pilot reported that in order to assist in the recovery, he drained all of the fuel out of the left fuel tank, and all but 5 gallons from the right tank the day after the accident. The recovery agent drained 5 gallons of fuel from the right fuel tank and no fuel from the left tank. The fuel selector valve had been disconnected so he could not tell what position it was in. The fuel screen was clean and clear of debris; the fuel manifold distribution valve was clean and contained no fuel. The spark plugs were in good condition. After several attempts, investigators started the engine and ran it up to 3,000 RPM. They were not able to run it long because the water pump belt was broken and they couldn't get coolant to flow. A shop owner in stockton said the airplane came in for an airshow in October, but had engine trouble. He rented the pilot shop space to work on the engine. He said the engine had a broken valve and the pilot repaired the engine himself. He said he advised the pilot to fly around the airport for an hour, but the pilot said he had run the engine on the ground for an hour and experienced no problems. The shop owner said he observed the takeoff and thought that the engine ran so rough that it could not become airborne. A company in stockton refueled this airplane and the pilot's T-6 during the airshow with a combined total of 90 gallons and had no records of refueling it since that time.