Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747 airplanes. This proposed AD would require repetitive mid- and low-frequency eddy current inspections for cracks in the overlapped skin panels in the fuselage skin lap joints in sections 41, 42, 44, and 46, and corrective actions if necessary. This proposed AD is prompted by a report indicating that an operator found multiple small cracks in the overlapped skin panels in the fuselage skin lap joints. We are proposing this AD to detect and correct cracks in the overlapped skin panels, which could join together and result in reduced structural capability in the skin and consequent rapid decompression of the airplane.