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 of the outboard nacelle struts to detect fatigue cracking of the strut skin and spring beam support fittings, and to detect cracked or loose fasteners of the support fittings; and corrective actions, if necessary. This amendment also provides for optional terminating action for the repetitive inspection requirements. This amendment is prompted by reports indicating that several cracked or broken spring beam support fittings were found on the outboard nacelle struts. The actions specified by this AD are intended to detect and correct such fatigue cracking and loose fasteners, which could result in failure of the outboard nacelle struts and consequent separation of the engine.