NTSB Identification: LAX87LA214.
The docket is stored on NTSB microfiche number 33623.
Accident occurred Friday, May 22, 1987 in SAN ARDO, CA
Probable Cause Approval Date: 05/09/1988
Aircraft: BOEING A75N1, registration: N90840
Injuries: 1 Serious.

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

DURING A PLEASURE CROSS COUNTRY FLIGHT, THE ENGINE EXPERIENCED A PARTIAL LOSS OF ENGINE POWER. THE PLT MADE A FORCED LANDING WHERE PRIOR TO TOUCHDOWN THE ACFT COLLIDED WITH POWER LINES THEN CONTACTED THE TERRAIN IN APRX THREE FT OF WATER. THE ACFT HAS HISTORY OF FOULED SPARK PLUGS RESULTING IN A ROUGH RUNNING ENGINE. THE SPARK PLUGS WERE REMOVED AND INSPECTED, NOTING THAT THE NUMBER 4 PLUG WAS FINGER TIGHT. FRONT AND BACK PLUGS 1, 2, 6, AND 7 DISPLAYED NORMAL OPERATING SIGNATURES. NUMBERS 3, 4, AND 5 WHEN REMOVED A CONSIDERABLE AMOUNT OF A WATER AND OIL MIXTURE DRAINED. A SANDY TYPE SUBSTANCE AND VEGETATION WERE NOTED ON THE PLUGS.THERE WAS NO MECHANICAL FAILURE OR MALFUNCTION NOTED IN THE REST OF THE SYSTEM.

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

REASON FOR OCCURRENCE UNDETERMINED


Contributing Factors

OBJECT..WIRE,TRANSMISSION


Contributing Factors

TERRAIN CONDITION..LOOSE GRAVEL/SANDY

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