What was found
THE NR 4 ENGINE OIL PRESSURE AND QUANTITY BEGAN TO FLUCTUATE AT THE TOP OF THE DESCENT 10 TO 15 PSI. THE CREW COMPLETED THE ABNORMAL CHECKLIST AND SECURED THE NR 4 ENGINE. MAINTENANCE INSPECTED AND FOUND THE NR 4 ENGINE OIL CAP TO BE UNSECURED. THE OIL WAS INSPECTED FOR FUEL. NONE WAS NOTED. THE OIL FILTER WAS INSPECTED FOR DEFECTS. NONE WERE NOTED. MAINTENANCE SERVICED THE ENGINE OIL AND COMPLETED AN ENGINE RUN. ALL PARAMETERS CHECKED NORMAL. ALL OTHER ENGINE OILS CAPS WERE INSPECTED FOR SECURITY, NO DEFECTS WERE NOTED.