What was found
(CAN) DURING ENGINE REMOVAL OF A PT6A-20 FROM A DHC-6-200, TWO OF THE TWELVE (12) LEFT HAND ENGINE MOUNT BOLT SHEARED OFF. 1 BOLT TOP MOUNT, 1 BOLT R/H SIDE MOUNT. BOTH BOLTS FOUND BROKEN OFF AT AREA WHERE SHANK AREA IS REDUCED . BOTH BOLTS TURNED APPROX 1/4 OF A TURN BEFORE THEY SHEARED. BOTH BOLTS ARE POST MODIFICATION T/1811. BOTH BOLTS APPEARED TO BE PROPERLY INSTALLED AND NOT BOTTOMED INTO ENGINE CASE.