Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747SP, and 747SR Series Airplanes

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747 series airplanes. That AD currently requires repetitive inspections to detect cracks in various areas of the fuselage internal structure, and repair if necessary. This new AD requires repetitive inspections of additional areas of the fuselage internal structure, and related investigative/ corrective actions if necessary. This new AD also removes certain requirements from the existing AD. This AD results from fatigue testing of the fuselage structure of a Boeing Model 747SR series airplane. We are issuing this AD to prevent the loss of the structural integrity of the fuselage, which could result in rapid depressurization of the airplane.