Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires repetitive inspections to detect cracks, corrosion, or damage of the lower spar fitting body and lug, and corrective actions, if necessary. This AD also provides for optional terminating action for the repetitive inspection requirements. This amendment is prompted by reports that fatigue cracking was found in the lower spar fitting lug on the number 3 pylon and in the lower spar fitting body. The actions specified in this AD are intended to detect and correct such fatigue cracking, which could result in failure of the strut and separation of the engine from the airplane.