NTSB Identification: LAX99LA065.
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Accident occurred Saturday, January 02, 1999 in DELANO, CA
Probable Cause Approval Date: 11/30/2000
Aircraft: Mooney M20K, registration: N1079G
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.

The pilot was on radar vectors for an ILS approach when a complete engine power loss occurred during IMC conditions. The pilot descended through the clouds and fog and collided with trees in an orchard. The pilot said he noticed the low voltage enunciator light illuminate then the oil pressure dropped to zero and the engine seized. Examination of the engine disclosed oil starvation damage and failures to the bearings and connecting rods. The oil pump drive gear was found separated from its shaft and loose in the accessory gear case. A metallurgical examination of the oil pump drive gear revealed rough machine marks located all around the fillet radius between the longitudinal shaft and web portions of the gear.

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

The fatigue failure and separation of the oil pump drive from the accessory gear section, which induced an oil starvation failure of the engine. The fatigue failure of the oil pump drive gear was caused by improper machining of the gear's fillet radius during original manufacture.

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