Airworthiness Directives; Boeing Model 777 Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 777 airplanes. This AD requires repetitive measurements of the freeplay of certain joints of the trailing edge flap supports; repetitive lubrication of the support joints; and related investigative and corrective actions if necessary. This AD also provides for modifying certain components of the trailing edge flap supports, which extends the intervals for the repetitive measurements, and revising the maintenance practices of the maintenance planning data document. This AD results from reports of excessive wear of the pins, bushings, and bearings, and corrosion at the joints of the outboard trailing edge flap supports. We are issuing this AD to prevent wear and corrosion at the flap support joints, which could result in loss of the trailing edge flap and possible loss of control of the airplane.