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

This document publishes in the Federal Register an amendment adopting airworthiness directive (AD) 2005-04-51 that was sent previously to all known U.S. owners and operators of certain Boeing Model 747-100B SUD, -200B, -200C, -200F, and -300 series airplanes by individual notices. This AD requires repetitive external detailed inspections for cracked skin or loose or missing fasteners of the body skin between body stations (BS) 420 and 460 inclusive and between stringers S-8 and S-12 inclusive on the left and right sides of the airplane, and a high frequency eddy current inspection for cracked frames if necessary. This AD also requires repair of any cracked frame or skin, and replacement of any loose or missing fastener. This AD is prompted by reports of large cracks common to fuselage frames in the upper deck area and severed or nearly severed adjacent frames. We are issuing this AD to detect and correct fatigue cracks in the frames and body skin at BS 420, 440, and 460 between stringers S-8 and S-12 inclusive, which could lead to severed frames, and consequent rapid decompression and loss of the structural integrity of the airplane.