What was found
AT 38,000, FT OIL QUANTITY ON THE NR 1 ENGINE DROPPED TO ZERO, OIL PRESSURE WAS IN AND OUT. WHEN PRESSURE DECREASED TO RED LINE, CREW SHUT DOWN THE ENGINE AND FLEW ON ONE ENGINE FOR 20 MINUTES UNTIL ARRIVAL. MAINTENANCE ACCOMPLISHED MAGNETIC CHIP DETECTOR IAW AMM 79-21-05. INSPECTED ENGINE AFTER IN-FLIGHT. WINDMILLING IAW AMM 71-00-00. FOUND STARTER SEAL LEAKING AND REPLACED LT ENGINE STARTER SEAL IAW AMM 80-11-01. ACCOMPLISHED SATISFACTORY OPERATIONAL CHECK. AIRCRAFT WAS GROUNDED.