What was found
(CAN) DURING SCHEDULED 100 HR INSPECTION, BROKEN OFF A PIECE OF CYLINDER NR 9 FOUND RESTING IN LOWER COWLING, FURTHER INVESTIGATION FOUND THE UPPER COWLING MOUNT BRACKET C/W REMAINING/BROKEN PIECE OF CYLINDER STILL ATTACHED IN COWL. CYLINDER NR 9 PUSH ROD HOUSING FOUND HEAVILY DINTED AS WELL AFT FACE OF PROPELLER FOUND GOUGED/MARKED. IT APPEARS THAT WHEN THE CYLINDER EAR FLANGE FAILED, PREVIOUS REPAIRED AT O/H. IT BOUNCED INTO THE ARC OF THE PROP WHILE IN OPERATION WHICH SENT IT BACK INTO THE PUSH ROD HOUSING CYLINDER ASSY. REPLACED WITH O/H UNIT, PROPELLER REMOVED FOR FURTHER ASSESSMENT, REPAIR PHOTOS AVAILABLE.