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Atlas / NTSB / LAX92FA064

NTSB CAROL · Event

Event LAX92FA064

1991-12-06 NUEVO, California, United States Fatal 1 aircraft Status: Completed

Aircraft involved

Probable cause & findings

THE FAILURE OF THE PILOT TO PERFORM PREVENTATIVE MAINTENANCE ON THE AIRPLANE'S POWERPLANT WHICH RESULTED IN A LOSS OF PERFORMANCE DURING AN UNKNOWN PHASE OF OPERATION. CONTRIBUTING TO THE ACCIDENT WAS FOULED SPARK PLUGS AND THE PARTIAL LOSS OF AIRCRAFT PERFORMANCE.

Factual narrative

THE AIRPLANE COLLIDED WITH RUGGED TERRAIN AFTER A LOSS OF ENGINE POWER. IT STRUCK THE NORTH FACE OF 20 DEG SLOPE OF AN EAST-WEST RIDGE, JUST BELOW THE CREST. THE AIRPLANE THEN SLID ABOUT 20 FT DOWN THE SLOPE WHERE A POST-IMPACT FIRE DESTROYED THE PLANE. AN EXAM OF THE ENGINE SPARK PLUGS REVEALED THE #1 & #3 CYLINDER SPARK PLUG GAPS WERE BRIDGED WITH CINDER-LIKE DEPOSITS WITH METALLIC GLOBULES STARTING TO FILL THE FIRING END CAVITY & WORN CENTER ELECTRODES. ACCORDING TO THE SPARK PLUG MANUFACTURER, SEVERELY FOULED PLUGS WILL OPERATE COLDER CAUSING MISFIRES, AND WILL ALSO MISFIRE AT HIGHER POWER BECAUSE OF THE CONDUCTIVE NATURE OF THE DEPOSITS AT ELEVATED TEMPS. BRIDGED GAPS WILL SHORT OUT THE SPARK PLUG. SUCH A MALFUNCTIONED PLUG WILL MISFIRE AT ALL POWER SETTINGS IN A MANNER SIMILAR TO A OIL FOULED PLUG. BRIDGED GAPS BRIDGED BY BEADED LEAD GLOBULE WILL NOT CLEAR UP BY ENGINE OPERATION & CAN BE CORRECTED ONLY BY REPLACING THE MALFUNCTIONING SPARK PLUG WITH A SERVICEABLE UNIT. THE ACDNT TIME WAS ESTD BE AT 1530 PST. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1991_LAX92FA064.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

Related research

What the literature says.

Academic papers and agency reports matching this event's aircraft type or causal vocabulary (maintenance). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.

Browse the full corpus — academia portal ↗