Airworthiness Directives; Boeing Model 777 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 777 series airplanes. This action requires repetitive inspections to detect cracking of the upper cutout and lower flange of the outboard support assembly of the flaperons on the wings; and corrective actions, if necessary. This amendment also provides an optional terminating action for the repetitive inspections. This amendment is prompted by results of flight testing conducted by the manufacturer indicating that high engine thrust conditions during takeoff cause excessive cyclic loads and could lead to fatigue cracking of the outboard support of the flaperon. The actions specified in this AD are intended to detect and correct such fatigue cracking, which could result in fracture of the flaperon support structure, loss of the flaperon, and consequent reduced controllability of the airplane.