NTSB LAX93FA042 — 1992-11-15 · CLEARLAKE, California, United States

N51198 has since been reassigned. It is now registered to a different aircraft (CESSNA 182T, built 2002), which was not involved in this event.

Aircraft involved

N51198 Cessna TU-206F Fatal

Probable cause & findings

THE EXHAUST VALVE FAILING DUE TO A COMPLETE FRACTURE WHICH RESULTED IN THE TOTAL LOSE OF ENGINE POWER. FACTORS IN THIS ACCIDENT WERE: 1) THE TERRAIN NOT BEING SUITABLE FOR A FORCED LANDING, AND 2) LOW AMBIENT LIGHT WHICH HAMPERED THE PILOT'S ABILITY TO SEE THE TERRAIN.

Factual narrative

THE PILOT AND HIS TWO PASSENGERS WERE IN CRUISE FLIGHT ON A VFR CROSS COUNTRY WHEN THE AIRPLANE'S ENGINE SUDDENLY BEGAN TO RUN ROUGH. THE PILOT, WHO WAS BEING FLIGHT FOLLOWED BY AN FAA CENTER, DECLARED AN EMERGENCY AND REQUESTED VECTORS TO A NEARBY AIRPORT. WITHIN ABOUT 2 MINUTES THE PILOT REPORTED THAT THE ENGINE COMPLETELY QUIT. THE PILOT ENTERED A POWER OFF FORCED LANDING AND COLLIDED WITH HILLY TERRAIN. NO SUITABLE TERRAIN WAS AVAILABLE FOR THE FORCED LANDING AND THE LIGHTING CONDITIONS WERE REPORTED AS 'DUSK TO DARK.' THE PILOT AND ONE OF HIS PASSENGERS RECEIVED FATAL INJURIES. AN OFF SITE EXAMINATION AND TEARDOWN OF THE ENGINE REVEALED THAT THE NUMBER 5 CYLINDER EXHAUST VALVE STEM BROKE JUST ABOVE THE VALVE HEAD. THE VALVE HEAD FELL INTO THE CYLINDER AND THE ACTION OF THE PISTON CAUSED A HOLE TO BE BROKEN THROUGH THE PISTON CENTER CROWN STRUCTURE. THE VALVE HEAD WAS FOUND WEDGED BETWEEN THE CRANKCASE STRUCTURE AND THE CRANKSHAFT, PREVENTING CRANKSHAFT ROTATION. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12

Verbatim from NTSB's published report. Source file NTSB_1992_LAX93FA042.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

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