Summary
We propose to adopt a new airworthiness directive (AD) for certain Model 777-200, -200LR, -300, and -300ER series airplanes. This proposed AD would require, for certain airplanes, replacing certain boost pump relays with ground fault interrupter (GFI) relays. For certain other airplanes, this proposed AD would require 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 proposed AD would require doing certain bond resistance measurements, and corrective actions if necessary. This proposed AD results from fuel system reviews conducted by the manufacturer. We are proposing this AD to prevent the potential of 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.