Amateur-built VANS RV-6A N6DJ accident near Arlington, Texas

Probable cause

A total loss of engine power due to the failure of both magnetos. Contributing to the accident was the lack of preventative maintenance/inspection of the magnetos.

NTSB analysis

While in cruise flight, the single-engine airplane experienced a total loss of engine power. During the forced landing, the airplane's nose wheel dug into the ground and the airplane nosed over, coming to rest in an inverted position. An on-site examination revealed both wing fuel tanks contained a considerable amount of fuel. Continuity to the back of the engine was confirmed. The engine was equipped with two single (left and right) magnetos, with the left magneto having an impulse coupling. The magneto's "p-leads", were disconnected and the engine rotated by hand; electric "spark" was not observed at the ignition leads. Further examination of the magnetos disclosed that they had "open" [bad] coils; and therefore produced little, if any, ignition spark. The magnetos were manufactured in 1991, and there was no maintenance record of any overhaul/maintenance preformed on the magnetos. According to the manufacturer, the magneto's coil, points, condenser, and brushes are to inspected every 500 hours and the magneto must be overhauled when the engine is overhauled.

Text from the NTSB. Open the NTSB docket for CEN09LA250 for the full record.