What was found
(CAN) NOISE WAS HEARD BY ENGINEER DURING MX WHILE MOVING CYCLIC FROM SIDE TO SIDE. AFTER THE BELLY SKIN WAS REMOVED A 5 INCH CRACK WAS FOUND IN ONE OF THE MAIN LONGERONS OF THE CABIN FLOOR. JUST BELOW WHERE THE CYCLIC MIXING UNIT ATTACHES. CRACK SEEMS TO HAVE ORIGINATED FROM ONE OF THE MANUFACTURES EXISTING RIVET HOLES. POSSIBLE AN IMPROPERLY DE-BURRED HOLE. AWAITING INSTRUCTIONS FROM MFG FOR REPAIR.