NTSB Identification: LAX95LA125.
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Accident occurred Saturday, March 04, 1995 in PACOIMA, CA
Probable Cause Approval Date: 11/06/1995
Aircraft: MOONEY M20J, registration: N11385
Injuries: 2 Minor.

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

AFTER OVERHAUL AT AN ENGINE FACILITY, THE ENGINE WAS INSTALLED IN THE AIRPLANE BY A MAINTENANCE SHOP. THE ENGINE WAS GROUND RUN FOR ONLY 40 MINS INSTEAD OF THE 2 HRS AND 25 MINS SPECIFIED BY LYCOMING. DURING THE TEST, AN OIL LEAK WAS FOUND IN THE AREA OF THE PROP GOVERNOR OIL PRESSURE LINE FITTING. THE FITTING WAS TIGHTENED AND THE AIRCRAFT PUT IN THE OWNER'S HANGAR. ON THE FIRST FLIGHT BY THE OWNER, THE ENGINE SEIZED AFTER 15 MINS. THE AIRCRAFT COLLIDED WITH OBSTRUCTIONS DURING THE FORCED LANDING. A LARGE SMEAR OF OIL WAS FOUND ON THE FUSELAGE BELLY AND LEFT SIDE. THE DISASSEMBLY OF THE ENGINE REVEALED DAMAGE CONSISTENT WITH LACK OF LUBRICATION DUE TO OIL EXHAUSTION. THE DIP STICK WAS IN PLACE AND ALL OIL LINES AND FITTINGS WERE TIGHT AND NOT LEAKING. WHEN THE PROP GOVERNOR WAS REMOVED ONLY A MS9144-01 SCREEN GASKET WAS FOUND INSTALLED. A RAISED CHANNEL AND OIL TRAIL WAS OBSERVED FROM A PRESSURE PORT IN THE GOVERNOR PAD UNDER THE GASKET TO THE PAD EDGE. LYCOMING'S PARTS MANUAL AND SERVICE INSTRUCTIONS SPECIFY THAT THIS ENGINE REQUIRES ANOTHER SPECIAL GASKET AND PLATE TO BE INSTALLED WITH THE MS9144-01 GASKET TO PREVENT OIL LEAKAGE. THE OVERHAUL SHOP WAS UNAWARE OF THE SPECIAL GASKET STACK REQUIREMENT AND DELIVERED THE ENGINE TO THE MAINTENANCE SHOP WITHOUT GASKETS ON THE GOVERNOR PAD. THE MAINTENANCE SHOP USED ONLY THE MOONEY MAINTENANCE MANUAL, WHICH DOES NOT MENTION SPECIAL GASKETS, FOR THE ENGINE INSTALLATION AND INSTALLED THE PROP GOVERNOR WITH ONLY THE MS9144 GASKET.

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

the failure of the engine overhaul shop to install the correct gasket stack on the propeller governor pad as required by the engine manufacturer.

Full narrative available

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