Airworthiness Directives; Boeing Model 747 Airplanes

The FAA is superseding an existing airworthiness directive (AD), which applies to all Boeing Model 747 airplanes. That AD currently requires a one-time inspection to determine whether the outer cylinder of the wing landing gear has certain part numbers, and replacement of the outer cylinder of the wing landing gear with a new, improved, or reworked part if necessary. That AD also requires removal of the load evening system, if such a system is installed. This new AD requires, for certain airplanes, an additional one-time inspection to determine whether the outer cylinder has a certain other part number. For those certain airplanes, this new AD also requires replacement of the outer cylinder with a reworked or new, improved part and related investigative and corrective actions, if necessary. This AD results from identification of an additional unsafe part. We are issuing this AD to prevent fracture of the outer cylinder of the wing landing gear, which could result in collapse of the wing landing gear.