Airworthiness Directives; The Boeing Company Airplanes

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 777 airplanes. This proposed AD was prompted by reports of unreliable performance of the fuel scavenge system. This proposed AD would require changing the main fuel tank water scavenge system, center fuel tank fuel scavenge system, certain electrical panels; related investigative actions, and corrective actions if necessary; and for certain airplanes, changing to give redundant control of the center override/jettison fuel pumps and main jettison fuel pumps. We are proposing this AD to prevent fuel exhaustion and subsequent power loss of all engines due to loss of capability to scavenge fuel in the center fuel tank.