AD FAA-2016-3992

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 787-8 airplanes. This AD was prompted by a report of uncommanded movement by a captain's seat during a landing rollout due to a failure in the seat horizontal actuator. This AD requires repetitive tests of the captain and first officer seat assemblies for proper operation, and corrective action if necessary. This AD also requires installation of new captain and first officer seat assemblies, which terminates the repetitive tests. We are issuing this AD to prevent a seat actuator clutch failure, which could result in a loss of seat locking and uncommanded motion of the captain's or first officer's seat; uncommanded seat movement could result in reduced controllability of the airplane.