What was found
HNL - FLT 420 - AT AN ALTITUDE OF 9,000 FEET, JUST AFTER LEVELING OFF, THE CAPTIN NOTED THE NR 1 ENGINE OIL PRESSURE DROPPING, MASTER WARNING FLASHED AND AURAL WARNING SOUND FOLLOWED BY A NR 1 ENGINE FLUCTUATING TORQUE INDICATION. SHUTDOWN PROCEDURES WERE INITIATED AND THE AIRCRAFT RETURNED SAFELY TO HONOLULU INTERNATIONAL. POST-FLIGHT INSPECTION OF THE NR 1 ENGINE REVEALED A FULL SUPPLY OF ENGINE OIL AND NO EXTERNAL INDICATIONS OF A MALFUNCTION. A MAINTENANCE TURN OF THE ENGINE WAS ATTEMPTED RESULTING IN A UNSUCCESSFUL START. FURTHER EVIDENCE SUGGESTED AN INTERNAL ENGINE SEIZE. THE NR 1 ENGINE WAS SUBSEQUENTLY REMOVED AND REPLACED WITH A SERVICEABLE ENGINE. (M)