Airworthiness Directives; Boeing Model 747 Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747 airplanes. This AD requires repetitive inspections of the dual side braces (DSBs), underwing midspar fittings, and associated parts; other specified actions; and corrective actions if necessary. This AD also provides an optional terminating action for the inspections and other specified actions. This AD is prompted by reports of corroded, migrated, and rotated bearings for the DSBs in the inboard and outboard struts, a report of a fractured retainer for the eccentric bushing for one of the side links of a DSB, and reports of wear and damage to the underwing midspar fitting on the outboard strut. We are issuing this AD to prevent the loss of a DSB or underwing midspar fitting load path, which could result in the transfer of loads and motion to other areas of a strut, and possible separation of a strut and engine from the airplane during flight.