Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747SR, and 747SP Series Airplanes

We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747- 200F, 747-300, 747-400, 747SR, and 747SP series airplanes. This AD requires inspecting for skin cracks at the shear tie end fastener locations of the fuselage frames, and repairing cracks if necessary. This AD results from a wide-spread fatigue damage assessment of Model 747 airplanes. We are issuing this AD to detect and correct cracks in the fuselage skin that can propagate and grow, resulting in a loss of structural integrity and a sudden decompression of the airplane during flight.