Airworthiness Directives; Boeing Model 777-200 and -300 Series Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 777-200 and -300 series airplanes. This AD requires repetitive detailed inspections of the forward lugs of the power control unit (PCU), yoke assembly, and forward attachment hardware of the left inboard, left outboard, right inboard, and right outboard flaperon PCUs; and other specified/corrective actions if necessary. For certain airplanes, this AD also requires other related concurrent actions. This AD results from reports indicating that operators have found worn, fretted, and fractured bolts that attach the yoke assembly to the flaperon PCU. We are issuing this AD to prevent damage and eventual fracture of the yoke assembly, pin assembly, and attachment bolts that connect the inboard and outboard PCUs to a flaperon, which could lead to the flaperon becoming unrestrained and consequently departing from the airplane. Loss of a flaperon could result in asymmetric lift and reduced roll control of an airplane. A departing flaperon could also cause damage to the horizontal and vertical stabilizers, which could result in loss of control of the airplane if damage is significant.