Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, -200B, -200C, -200F, -300, - 400, -400D, and -400F series airplanes. This proposed AD was prompted by reports of significant fuselage skin damage at certain parts of the dorsal fairing, due to wear from the dorsal fairing. This proposed AD would require repetitive detailed inspections for wear and cracks of the fuselage skin under the dorsal fairing, and related investigative and corrective actions if necessary. This proposed AD would also require repetitive post-repair external surface high frequency eddy current inspections of the blended areas of the skin and detailed inspections of the unrepaired areas, and related investigative and corrective actions if necessary. We are proposing this AD to detect and correct fuselage skin damage of the dorsal fairing area, which could result in skin cracking and consequent depressurization of the airplane.