WPR09LA454

During cruise flight the engine lost all power. The pilot did not have enough time and altitude to perform an engine restart, and during the subsequent forced landing, the airplane nosed over. The airplane was equipped with an automotive engine converted for aviation use. Post accident examination revealed that the engine's only magneto had failed after its rotor was damaged by a loose high tension lead attachment screw. The airplane sustained substantial damage to the fuselage, wings, and vertical stabilizer during the accident sequence.

HISTORY OF FLIGHT On September 18, 2009, at 0915 Pacific daylight time, an experimental, amateur-built, Lewis Jennings Nieuport 11 biplane, N124LH, nosed over during a forced landing near Pahrump, Nevada. The pilot was operating the airplane under the provisions of 14 Code of Federal Regulations Part 91. The certificated sport pilot sustained minor injuries. The airplane sustained substantial damage to the fuselage, wings, and vertical stabilizer. The local personal flight departed Calvada Meadows Airport, Pahrump, about 0835. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported flying the airplane for approximately 40 minutes when the engine lost power. He was at an altitude of approximately 1,000 feet agl, and stated that he did not have sufficient time to perform an engine restart. Prior to losing power he had been monitoring the engine oil pressure and temperature, and reported that they were within normal limits. AIRCRAFT INFORMATION The single-seat, experimental airplane, was issued a Special Airworthiness Certificate on January 4, 2007. It was powered by a four-cylinder, air-cooled, 1835 cc Volkswagen automobile engine, and equipped with a two-blade wooden propeller. The pilot reported that the engine was overhauled in February 2009, and installed on the airplane approximately 8 flight hours prior to the accident. TESTS AND RESEARCH Engine A single Taylor Cable Products, Vertex automotive magneto provided ignition for the engine. Post accident examination of the magneto revealed that the high tension cable screw for cylinder number two had become unscrewed from its mounting post within the magneto distributor head. The screw was located within the magneto housing, and signature marks indicated that it had made contact with the rotor arm. The rotor arm was bent downwards, and the rotor case had become disconnected from the shaft. Rotation of the engine did not produce a corresponding rotation of the rotor. The design of magneto was such that the high tension leads were held in place within the distributor head with tapered screws. The screws were designed to hold the high tension lead in place, and bridge the inner conductor to its respective contact within the head. A representative from Taylor Cable Products stated that the magneto was manufactured in January 1996. He further stated that the magneto was designed for automotive use, and as such did not have specific provisions for locking the high tension screws in place.