Action
Final rule.
Summary
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes. This AD requires inspections for scribe lines in affected lap and butt splices, wing-to-body fairing locations, and external repair and cutout reinforcement areas; and related investigative and corrective actions if necessary. This AD was prompted by reports of scribe lines found at lap joints and butt joints, around external doublers and antennas, and at locations where external decals had been cut. We are issuing this AD to detect and correct scribe lines, which can develop into fatigue cracks in the skin and cause sudden decompression of the airplane.