Events
The aircraft lost engine power and collided with trees in mountainous terrain. The pilot reported that the loss of power was gradual and accompanied by engine roughness. The pilot attempted to restart the engine but did not manipulate the magneto switch as outlined in the Pilot Operating Handbook amplified emergency procedures.
Engine Examination
Examination of the engine magnetos revealed that the left magneto internal timing was incorrect. The breaker point cam and cam follower were found worn. Additionally, the installed magneto, a Slick model 4201-R, is not an approved installation on Lycoming engines.
Maintenance Records
Maintenance records did not show that new or overhauled magnetos were installed at the time of the engine overhaul or replaced after the engine was overhauled. Review of the engine logbook indicated that the magneto timing was adjusted about 78 flight hours before the accident, during the last 100-hour inspection.