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While in cruise flight, the crew of the SA 227 aircraft noticed the left engine oil pressure fluctuating. A visual inspection of the engine in-flight revealed nothing unusual. A short time later, the left engine oil warning light illuminated and, in accordance with company standard operating procedures, a precautionary engine shut down was carried out. The crew then diverted the aircraft to the nearest available airport and conducted a single engine approach and landing. A post flight inspection of the aircraft revealed no measurable oil remaining in the left engine.

An inspection of the aircraft, immediately following landing, found that the engine oil had leaked from a loose right-angle oil line fitting that was situated on the left engine's Beta Manifold. A subsequent maintenance investigation by the operator discovered that the fitting had become loose after it had been forcibly contacted by the left starter generator's "micarta" electrical connector block. That contact had occurred following the rotation of the generator on its mounts due to a loose attaching clamp and several missing locating pins.

An inspection of the generator's attaching "v-band" clamp revealed evidence of deterioration of the thread and nut that tightened the clamp. Three of the four locating pins that positioned the generator on the mount were also noted to have been missing, with the remaining pin partially depressed into the surface of the mount. The generator had been removed, and re-installed, during contractor maintenance approximately two weeks prior to the incident.

The starter generator and mounts were replaced with serviceable items and the engine was ground run with no problems noted. The aircraft was returned to service.

Following the incident the contract maintenance personnel were briefed on the occurrence and the ramifications of incorrect component installation.

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