As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE AT 13,000 FT, PILOT NOTICED NR 1 ENGINE TORQUE INDICATOR FLUCTUATING. NOTICED NR1 OIL PRESSURE INDICATION DROPPED. PULLED BACK POWER ON ENGINE AND SHUTDOWN NR 1 ENGINE. DECLARED AN EMERGENCYAND COMPLETED A SINGLE ENGINE LANDING WITHOUT INCIDENT. AN INSPECTION WAS PERFORMED. FOUND OIL FILLER CAP NOT SECURED PROPERLY, CAUSING OIL TO BE VENTED FROM THE OIL FILLER TUBE.