What was found
FLIGHT 843 DEPARTED MIA AND DURING THE CLIMB THE CREW REPORTED NR 1 ENGINE LOW OIL PRESSURE LIGHT CAME ON DURING FLIGHT FOLLOWED BY F/E'S OIL PRESSURE GAUGE DROPPED TO 5 TO 10 PSI, SHUT DOWN NR 1 ENGINE PER AMJ CHECKLIST, DUMPED FUEL AND RETURNED TO MIA. THE NR 1 ENGINE WINDMILLED FOR 15 MIN. AFTER SHUT DOWN, AMERIJET MAINTENANCE TROUBLESHOT THE NR 1 ENGINE LOW OIL PRESSURE, THE NR 1 ENGINE OIL PUMP IS SUSPECTED TO HAVE FAILED. REPLACED THE NR 1 ENGINE GEARBOX ASSY INCLUDED IN THE GEARBOX ASSY IS THE ENGINE OIL PUMP. REMOVED AND REPLACED GEARBOX. LEAK CHECK AND OPERATIONAL CHECK TEST -B- IAW MM CH 71-00-00, ALL PARAMETERS NORMAL PER MM CH 71-00-00 NO LEAKS NOTED. THE AIRCRAFT WAS RETURNED TO SERVICE.