Airworthiness Directives; Boeing Model 747-100, -200, and -300 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-100, -200, and -300 series airplanes. This action requires repetitive detailed visual and/or borescope inspections to detect discrepancies of certain areas of the wing strut. This amendment also provides for an optional terminating action for the repetitive inspections. This amendment is prompted by reports that fatigue cracking was found in the vertical chords, midspar webs, and canted closure webs. The actions specified in this AD are intended to detect and correct fatigue cracking and stress corrosion of the wing strut, which could result in failure of the strut-to-wing interface, and consequent separation of the engine and strut from the airplane.