This March 2009 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Stewart P-51. Injuries: 1 Fatal. Location: Ocala, Fla. Aircraft damage: Destroyed.
What reportedly happened: The 80-year-old pilot, who had logged 13,917 hours, also held a mechanic certificate with airframe and powerplant ratings. According to several people who knew the pilot, he was a former test pilot on the North American P-51 airplane. He had purchased the disassembled experimental amateur-built airplane from its builder six years earlier. He was attempting to reassemble the airplane, and spent several months attempting to resolve fuel leaks in the airplane’s integral wing tanks. Subsequent to the pilot’s use of a slosh sealant in the fuel tanks, the engine lost power during two separate high-speed taxi tests due to clogged fuel screens. The day before the accident, the pilot conducted his first flight in the airplane, which lasted about 18 minutes. The accident happened on the second flight. According to witnesses, the airplane was at low altitude and the engine sounded as if it was not producing power or had stopped. The airplane banked sharply in order to avoid a 500-foot-tall cell phone tower, then hit the ground and burst into flames.
The airplane assembly guide specified the use of a commercial sealant called Pro-Seal during fuel tank assembly, but did not specify or prohibit the use of a slosh sealant, which was intended to be used after assembly. The technical information for the slosh sealant that was found in the pilot’s hangar stated that the condition and cleanliness of the surface can affect sealant adhesion.
Examination of the wreckage revealed that the interior surfaces of the wing bays that were used to contain fuel exhibited a charred brown/black material consistent with a fire-damaged internal tank coating. One in-tank fuel pickup finger screen was partially occluded by the material, but the pre-accident condition of the finger screen could not be determined.
Probable cause: A loss of engine power due to contamination and clogging of the fuel system by a post-assembly fuel tank sealant.
For more information: NTSB.gov