Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-200C, -200F, -400, -400D, and -400F series airplanes. This proposed AD would require repetitive inspections for cracks in the overlapping (upper) skin, upper fastener row of the lap joints of the fuselage skin in sections 41, 42, and 46; and related investigative and corrective actions, if necessary. This proposed AD results from fatigue tests and an analysis that identified areas of the fuselage lap joints where fatigue cracks can occur. We are proposing this AD to detect and correct fatigue cracks in the overlapping (upper) skin, upper fastener row of the lap joints of the fuselage skin in sections 41, 42, and 46, which could adversely affect the structural integrity of the airplane.