Airworthiness Directives; Lockheed Model L-1011-385 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Lockheed Model L-1011-385 series airplanes, that currently requires revision of the Airplane Flight Manual (AFM) to prohibit operation of the fuel boost pumps when fuel quantities are below certain levels, and to add maintenance procedures for operating the airplane under certain conditions. That AD also requires the installation of a placard on the engineer's fuel panel to advise the maintenance crew that operation of the fuel boost pumps is prohibited under certain conditions. This amendment adds a terminating modification for the requirements of the existing AD. This amendment is prompted by reports of internal electrical failures in the fuel boost pump of the wing fuel tanks that could result in either electrical arcing or localized overheating. The actions specified by this AD are intended to prevent such electrical arcing or overheating, which could breech the protective housing of the fuel boost pump and expose it to fuel vapors and fumes, and consequent potential fire or explosion in the wing fuel tank.