What was found
DURING DECENT, THE LT ENGINE INDICATED A WARNING FOR LOW OIL PRESSURE. THE WARNING SHOWED LOW OIL PRESSURE ON THE CAP AND LOCAL ALERT, WITH AN OIL PRESSURE FLUCTUATION IN THE CAUTION AND WARNING AREAS. THE PILOT SHUT THE ENGINE DOWN IAW THE QRH CHECK LIST REQUIREMENTS. AN EMERGENCY WAS DECLARED AND THE AIRCRAFT LANDED SAFELY. MAINTENANCE FOUND THE ENGINE OIL CAP OFF AND THE ENGINE COVERED IN OIL. ENGINE WAS SERVICED WITH ELEVEN QUARTS OF OIL AND RAN AT 60 PERCENT TORQUE FOR FIVE MINUTES AND 35 PERCENT TORQUE FOR FIVE MINUTES. LEAK AND OPERATIONS CHECKS GOOD. AIRCRAFT OK FOR SERVICE.