What was found
AIRCRAFT STARTED EXPERIENCING LOSS IN OIL PRESSURE INDICATED BY THE LHS ENGINE OIL PRESSURE GAUGE NEEDLE BOUNCING BETWEEN THE RED MARKINGS ON THE GAUGE, THE NEEDLE AFTER A FEW SECONDS SETTLED DOWN IN THE GREEN AND THEN SLOWLY STARTED DECREASING, ON NOTICING THIS THE PIC DECIDED TO SHUT DOWN THE NR 1 LHS ENGINE IAW EMERGENCY PROCEDURES CHECKLIST AND FIND THE CLOSEST AIRPORT TO LAND. THEY PERFORMED AN EMERGENCY PROCEDURES LANDING AT ABOUT 6:30 PM, ON 11/10/2007 AT AIRPORT. ON INSPECTING THE AC IT WAS FOUND THAT THE OIL FILLER CAP O-RING WAS MISSING AND THAT HAD CAUSED THE OIL TO DEPART THE ENGINE. ACCESS AIR PILOTS HAVE BEEN INSTRUCTED ON INSPECTING THE OIL FILLER CAPS O-RINGS FOR DAMAGE OR LOOSENESS, ACCESS AIR HAS ALSO NOW IMPLEMENTED PROCEDURES WHERE THE OIL FILLER CAP O-RING WILL BE REPLACED EVERY MONTH BY TRACKING IT ON THE COMPONENT STATUS SHEET. (K)