Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 777 airplanes. This proposed AD would require 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. The proposed AD also provides for modifying certain components of the trailing edge flap supports, which would extend the intervals for the repetitive measurements, and revising the maintenance practices of the maintenance planning data document. This proposed 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 proposing 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.