AD FAA-2019-0188

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 747-200B, 747-200C, 747-200F, 747-300, 747- 400, 747-400D, 747-400F, 747-8F, and 747-8 series airplanes. This AD was prompted by reports of uncommanded fore and aft 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 for certain airplanes, and applicable on-condition actions. This AD also requires an inspection to determine the part number and, if applicable, the serial number of the Captain's and First Officer's seats, and applicable on-condition actions. This AD also provides an optional terminating action for the repetitive actions for certain seats. The FAA is issuing this AD to address the unsafe condition on these products.