What was found
DURING A ROUTINE INSPECTION, CRACKS WERE FOUND IN THE CABIN STRUCTURE FORWARD OF THE MAIN DOOR. CRACKING WAS FOUND THROUGH RIVET HOLES, AND RIVETS WERE FOUND WORKING/LOOSE. THIS CRACKING IS SUSPECTED TO BE CAUSED BY FORCES IMPOSED ON CABIN DOOR, WHICH IS MOUNTED ADJACENT TO WEB. THE CABIN DOOR IS USED AS A HANDHOLD BY PILOTS CLIMBING IN AND OUT OF AIRCRAFT WHICH CAUSES STRAIN ON CABIN DOOR STRUCTURE.