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