NTSB Identification: LAX92FA289.
The docket is stored on NTSB microfiche number 47449.
Accident occurred Thursday, July 09, 1992 in SUPERIOR, AZ
Probable Cause Approval Date: 06/30/1993
Aircraft: CESSNA T210N, registration: N6483C
Injuries: 1 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
THE CERTIFICATED PRIVATE PILOT, THE SOLE OCCUPANT, WAS ON A CROSS COUNTRY BUSINESS FLIGHT WHEN THE ENGINE QUIT. THE PILOT MADE A FORCED LANDING ABOUT 250 FEET SHORT OF A DIRT AIRSTRIP. THE AIRPLANE WAS DESTROYED BY IMPACT AND A POST IMPACT FIRE, AND THE PILOT WAS FATALLY INJURED. EXAMINATION OF THE ENGINE REVEALED A BROKEN CRANKSHAFT ON THE CRANKCHEEK ADJACENT TO THE NUMBER 1 CYLINDER. THE CRANKSHAFT HAD BEEN REPLACED 42 HOURS PRIOR TO THE ACCIDENT. THE CRANKSHAFT WAS SUPPLIED FROM AN ENGINE WITH AN ACCUMULATED TOTAL TIME OF ABOUT 1,000 HOURS OF OPERATION THAT HAD PREVIOUSLY SUSTAINED A SEPARATION OF THE NUMBER 1 CYLINDER FROM THE ENGINE CASE. AFTER AN INSPECTION, THE CRANKSHAFT WAS DETERMINED TO BE SERVICEABLE AND INSTALLED IN THE ACCIDENT AIRPLANE'S ENGINE. METALLURGICAL EXAMINATION REVEALED A HIGH CYCLE FATIGUE FAILURE CONSISTENT WITH SURFACE INITIATED CRACKING. A METALLURGICAL REPORT INDICATED THAT SURFACE CRACKING WOULD NOT BE EXPECTED IN THE AREA OF FAILURE UNLESS PRIOR DAMAGE TO THE SURFACE HAD OCCURRED.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: AN INADEQUATE MAJOR ENGINE OVERHAUL PROCEDURE, DURING WHICH PREVIOUS CRANKSHAFT DAMAGE WAS NOT DETECTED. CONTRIBUTING TO THE ACCIDENT WAS A SURFACE INITIATED FATIGUE FAILURE OF THE ENGINE CRANKSHAFT.
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