What was found
(CAN) DURING ROUTINE INSPECTION ALUMINUM FLAKES WERE FOUND IN THE OIL SCREEN. THERE WAS ALSO SEVERAL PIECES OF ALUMINUM IN THE OIL FILTER CAP AND IN THE SUMP PLUGS. REMOVAL OF THE NR 1 CYLINDER, TO FACILITATE THE INVESTIGATION, REVEALED THE MAIN CRANKCASE REAR WEB WAS COMPLETELY CRACKED CIRCUMFERENCIALLY AROUND THE MAIN BEARING JOURNAL, WITH ANOTHER CRACK INITIATING FROM THE BEARING AREA. NO UNUSUAL VIBRA TIONS OR INDICATIONS WERE REPORTED BY THE PILOT.