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

This document publishes in the Federal Register an amendment adopting airworthiness directive (AD) 2002-24-52 that was sent previously to all known U.S. owners and operators of all Boeing Model 747-400, -400D, and -400F series airplanes by individual notices. This AD continues to require revising the Airplane Flight Manual to require the flightcrew to maintain certain minimum fuel levels in the center fuel tanks, and to prohibit the use of the horizontal stabilizer fuel tank. This AD also removes the reference to placards that was specified in the operating limitations required by another AD. This action is prompted by reports indicating that two fuel pumps showed evidence of extreme localized overheating of parts in the priming and vapor pump section of the fuel pump. Such overheating provides an ignition source in the fuel tank during dry running of the pump, which could result in fire/explosion of the fuel tank. The actions specified by this AD are intended to require the flightcrew to maintain certain minimum fuel levels in the center fuel tanks, and to prohibit the use of the horizontal stabilizer fuel tank.