Airworthiness Directives; The Boeing Company Model 777-200, -200LR, -300, and -300ER Series Airplanes

We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires, for certain airplanes, replacing certain boost pump relays with ground fault interrupter (GFI) relays. For certain other airplanes, this AD requires installing new panels in the main equipment center, making certain wiring changes, installing new GFI relays in the new panels, and installing new electrical load management system (ELMS) software. For certain other airplanes, this AD requires doing certain bond resistance measurements, and corrective actions if necessary. This AD was prompted by fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent potential ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.