NTSB Identification: LAX92LA327.
The docket is stored on NTSB microfiche number 47385.
Accident occurred Friday, July 31, 1992 in GLENDALE, AZ
Probable Cause Approval Date: 09/14/1993
Aircraft: ROCKWELL 112TC, registration: N4581W
Injuries: 1 Uninjured.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

THE ACCIDENT SEQUENCE WAS WITNESSED BY SEVERAL A & P MECHANICS WORKING AT THE GLENDALE AIRPORT. ONE WITNESS SAID THE ENGINE SEEMED TO BE RUNNING ROUGH AND BACKFIRING DURING THE PRETAKEOFF ENGINE RUNUP. THE AIRCRAFT INITIATED A TAKEOFF AND THE WITNESSES REPORTED THAT THE ENGINE ROUGHNESS AND BACKFIRING CONTINUED THROUGHOUT THE TAKEOFF GROUND ROLL AND INITIAL CLIMB. THE AIRCRAFT WAS OBSERVED TO MANEUVER TO THE DOWN WIND LEG AS IF THE PILOT WERE ATTEMPTING TO RETURN FOR A LANDING, THEN THE ENGINE CEASED RUNNING ALTOGETHER. THE AIRCRAFT COLLIDED WITH THE GROUND IN A CORN FIELD ABOUT ONE HALF MILE FROM THE END OF THE RUNWAY AND SHEARED OFF THE LANDING GEAR. EXAMINATION OF THE ENGINE BY AN A & P MECHANIC UNDER THE SUPERVISION OF FAA INSPECTORS REVEALED THAT THE NUMBER ONE CYLINDER EXHAUST VALVE WAS STUCK IN THE OPEN POSITION DUE TO CARBON BUILDUP ON THE VALVE STEM.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A LOSS OF ENGINE POWER DUE TO EXCESSIVE CARBON DEPOSITS ON THE NUMBER ONE CYLINDER EXHAUST VALVE, AND, THE PILOTS ATTEMPTED OPERATION OF THE AIRCRAFT WITH KNOWN MECHANICAL DEFICIENCIES.

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