Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 747 series airplanes. This action requires a one-time inspection of the fuselage skin of the aft lower body for certain repair doublers, and follow-on inspections and corrective actions if such doublers are installed. For certain airplanes, this action includes optional repetitive inspections of the fuselage skin for scratches or cracking. This action is necessary to find and fix possible fatigue cracking of the fuselage skin concealed under certain repair doublers, which could result in rapid decompression of the airplane. This action is intended to address the identified unsafe condition.