Accident Overview
On April 14, 2009, at approximately 1915 central daylight time, a single-engine RV-6A airplane, registration N6DJ, was substantially damaged during a forced landing following a loss of engine power shortly after takeoff from Arlington Municipal Airport (GKY) in Arlington, Texas. The pilot, who was the sole occupant, received minor injuries. The airplane was registered and operated by a private individual. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 flight.
Examination
According to a Federal Aviation Administration (FAA) inspector who responded to the site, the pilot reported that he was on a local pleasure flight when the aircraft experienced a loss of engine power. The pilot elected to conduct a forced landing in a vacant field. During the landing, the airplane's nose wheel dug into the ground and the airplane nosed over, coming to rest inverted.
On April 15, 2009, the NTSB Investigator in Charge (IIC) and a technical representative from the engine manufacturer examined the airplane on-site. The airplane was turned right side up; the fuel selector was found in the left position and both wing fuel tanks contained a considerable amount of fuel. The electric fuel boost pump was in working order. The bottom set of spark plugs were removed from the cylinders and the engine was rotated by hand. Continuity to the back of the engine was confirmed.
The engine was equipped with two single magnetos (left and right), with the left magneto having an impulse coupling. The magneto p-leads were disconnected and the engine was rotated by hand; no electric spark was observed at the ignition leads. The magnetos were removed for further examination.
Magneto Issues
The magnetos were tested under the supervision of the NTSB IIC and the engine manufacturer's representative. When placed in a bench test machine, the left magneto did not produce any ignition spark; individual components were then tested. The ignition technician stated that the left magneto displayed signs that its coil was open. The right magneto produced an erratic electric spark and would stop producing spark around 1200-1500 rpm. When testing the individual components of the right magneto, the coil also tested open.
The Slick magnetos, model 4370 and 4371, were manufactured in 1991. A review of the aircraft maintenance logs did not reveal any data indicating that the magnetos had ever been overhauled or maintained. According to the Slick Magneto Maintenance and Overhaul manual, the magneto's coil, points, condenser, and brushes are to be inspected every 500 hours and the magneto must be overhauled when the engine is overhauled.