Airworthiness Directives; Boeing Model 747 Series Airplanes Equipped With General Electric Model CF6-45 or -50 Series Engines; or Pratt & Whitney Model JT9D-3, -7, or -70 Series Engines; and 747-E4B (Military) Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes and all 747- E4B (military) airplanes. This action requires repetitive inspections to detect cracking or fracture of the steel attachment fittings of the diagonal brace to the nacelle struts; and replacement of the attachment fittings with new steel fittings, if necessary. This amendment is prompted by a report indicating a fractured steel attachment fitting of a diagonal brace to the number 2 nacelle strut; such fracture has been attributed to fatigue cracking. The actions specified in this AD are intended to detect and correct such fatigue cracking, which could result in failure of a nacelle strut diagonal brace load path and possible separation of the nacelle from the wing.