AD FAA-2018-0711

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 757-200 series airplanes. This AD was prompted by reports of uncommanded movement of the captain's and first officer's seats. This AD requires, for the captain's and first officer's seats, repetitive horizontal actuator identifications, repetitive checks of the horizontal movement system (HMS), a detailed inspection of the HMS, as applicable, and applicable on-condition actions. This AD also requires a general visual inspection to determine the seat part numbers of the captain's and first officer's seats, a cable adjustment check on seats with certain seat part numbers, and applicable on-condition actions. We are issuing this AD to address the unsafe condition on these products.