NTSB Identification: LAX86FA326.
The docket is stored on NTSB microfiche number 33867.
Accident occurred Tuesday, August 19, 1986 in WILMINGTON, CA
Probable Cause Approval Date: 01/25/1988
Aircraft: CESSNA 182N, registration: N92252
Injuries: 2 Serious.

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.

DURING A LOCAL NIGHT INSTRUCTIONAL FLT THE PLTS REPORTED THAT THE ENG BEGAN TO RUN VERY ROUGH AND EVENTUALLY QUIT WHEN POWER WAS REDUCED SLIGHTLY TO BEGIN THE DESCENT FOR THE DESTINATION ARPT. THE ACFT STRUCK POWER LINES, TWO SMALL BUILDINGS AND A BRICK WALL DURING THE NIGHT FORCED LANDING IN AN INDUSTRIAL AREA. EXAMINATION OF THE ENG REVEALED THAT THE NUMBER ONE CYLINDER EXHAUST VALVE ROCKER ARM SHAFT BOSS JOURNAL HAD FAILED. TESTS OF AN IDENTICAL ENG DUPLICATING THE BOSS JOURNAL FAILURE IN A TEST CELL REPLICATED THE ENG POWER LOSS AS DESCRIBED BY THE CREW. THE CYLINDER HAD BEEN CHANGED 27 HOURS PRIOR TO THE ACCIDENT. EVIDENCE INDICATED THAT THE ROCKER ARM SHAFT KEEPER BOLT HAD BEEN OVER TORQUED DURING THE OVERHAUL.

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

ENGINE ASSEMBLY,VALVE,INTAKE..INOPERATIVE

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

ENGINE ASSEMBLY,OTHER..OVERTORQUE

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

MAINTENANCE,INSTALLATION..IMPROPER..OTHER MAINTENANCE PERSONNEL

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

DOCUMENTATION..IMPROPER..OTHER MAINTENANCE PERSONNEL


Contributing Factors

TERRAIN CONDITION..NONE SUITABLE


Contributing Factors

OBJECT..WIRE,TRANSMISSION


Contributing Factors

OBJECT..FENCE


Contributing Factors

OBJECT..BUILDING(NONRESIDENTIAL)


Contributing Factors

ACFT/EQUIP,INADEQUATE STANDARD/REQUIREMENT..MANUFACTURER

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