What was found
AN ULTRASONIC (UT) INSPECTION OF THE M/R BLADE BOLTS RETAINING THE MAIN ROTOR BLADE SPAR TO THE BLADE CUFF WAS PERFORMED IAW THE MANUFACTURER'S INSTRUCTIONS. DURING THE UT INSPECTION, CRACKS WERE DETECTED ON ONE OR MORE BOLTS ON EACH BLADE. BOLTS THAT WERE REMOVED FOR CRACK CONFIRMATION, CORROSION WAS EVIDENT ON THE BOLT SHANK APPROXIMATELY .500 INCH BELOW THE BOLT HEAD AND EXTENDING FOR APPROXIMATELY 1.000 INCH ALONG THE SHANK. THE CRACKS WERE NOTED TO OCCUR WITHIN THE CORRODED AREAS. NO CRACKING WAS NOTED OUTSIDE OF THE CORRODED AREAS.