Airworthiness Directives; Boeing Model 747 Series Airplanes Equipped with Pratt & Whitney JT9D-3 or JT9D-7 Series Engines (except JT9D-70 Series Engines)

This amendment adopts a new airworthiness directive (AD), applicable to Boeing Model 747 series airplanes equipped with Pratt & Whitney JT9D-3 or JT9D-7 series engines (except JT9D-70 series engines), that requires detailed inspections of the upper and lower surface of the forward lower spar of the nacelle strut for cracking or other damage, and for any loose or damaged fasteners. This amendment also requires replacement of loose or damaged fasteners and, if necessary, associated repair of the forward lower spar. This action is necessary to detect and correct cracking or other damage to the upper or lower surface of the forward lower spar and any loose or damaged fasteners, which could result in reduced structural capability of nacelle struts one through four, and possible separation of a strut and engine from the airplane during flight. This action is intended to address the identified unsafe condition.