Summary
We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 777-200 series airplanes. This proposed AD would require repetitive inspections for any wrinkle in certain external skin panels, and for cracking at the fuselage bulkhead shear tie end fastener locations at certain stations of section 48 of the fuselage; and doing related investigative and corrective actions if necessary. This proposed AD results from a report of cracks found in the external skin on the left and right sides of the Section 48 panel of the fuselage on two airplanes with skin wrinkles found at two of the external crack locations. We are proposing this AD to detect and correct wrinkles and cracks in certain external skin panels of Section 48, which could join together and result in reduced structural integrity of support structure for the vertical and horizontal stabilizers and inability of the airplane to sustain limit loads.