Airworthiness Directives; Boeing Model 747-400 and -400D Series Airplanes

We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-400 and -400D series airplanes. This AD requires installing new relays to allow the flightcrew to turn off electrical power to the in-flight entertainment (IFE) system and other non- essential passenger cabin systems through the left and right utility bus switches, and other specified actions. This AD results from an IFE systems review. We are issuing this AD to ensure that the flightcrew is able to turn off electrical power to the IFE system and other non- essential passenger cabin systems through utility bus switches in the flight compartment, in the event of smoke or fumes. The flightcrew's inability to turn off electrical power to the IFE system and other non- essential passenger cabin systems could result in the inability to control smoke or fumes in the airplane flight deck or passenger cabin during a non-normal or emergency situation.