What was found
PILOT REPORTED OIL PRESSURE FLUCTUATION DURING FLIGHT, BUT NEVER OUT OF GREEN ARC. UPON LANDING, NOTED ENGINE HAD HAD A MAJOR OIL LEAK. UPON INVESTIGATION, FOUND ONE OF THE THROUGH-BOLT NUTS HAD CRACKED, THIS WAS LOCATED ON THE FWD LOWER PART OF THE CASE. THE ENGINE HAD LOST ALMOST 6 QUARTS OF 0.1 ON A ONE-HOUR FLIGHT. LOOKING AT NUT WITH A 10-POWER MAGNIFYING GLASS, NOTED A LOT OF MACHINING MARKS LEFT ON IT.