As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW EXPERIENCED LT ENGINE OIL PRESSURE FLUCTUATING. UPON COMPLETING EMERGENCY CHECK LIST OIL PRESSURE DROPPED BELOW 20PSI AND ENGINE WAS SHUT DOWN. SUBSEQUENT INSPECTION REVEALED A PINCHED O-RING IN THE MAIN ENGINE OIL FILTER HOUSING. O-RING WAS REPLACED AND ENGINE MAINTENANCE MANUAL PROCEDURES WERE ACCOMPLISHED,ENGINE OIL SERVICED AND ENGINE PERFORMANCE RUN ACCOMPLISHED.