Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes, that requires repetitive inspections to detect evidence of wear damage in the area at the interface between the vertical stabilizer and fuselage skin, and corrective actions, if necessary. This amendment also provides for an optional terminating action for the repetitive inspections. The actions specified by this AD are intended to detect and correct wear damage of the fuselage skin, which could result in thinning and cracking of the fuselage skin, and consequent in-flight depressurization of the airplane. This action is intended to address the identified unsafe condition.