What was found
MIA - NR 4 ENGINE OIL PRESSURE DROPPED TO 32 PSI. SHUTDOWN ENGINE AS PER ABNORMAL CHECKLIST. WINDMILL SPEEDS WERE N1, 13.5 PERCENT, N2 21 PERCENT, OIL PRESS 3 PSI. AIRCRAFT RETURNED TO MIAMI WITHOUT INCIDENT. REMOVED AND REPLACED NR 4 ENGINE OIL PUMP ASSY IAW MM 72-60-00. OPS CHECK OK ON ENGINE RUN IAW ARROW AIR J/C 6527. (M)