Airworthiness Directives; Lockheed Model L-1011 Series Airplanes Equipped With Rolls-Royce Model RB211-524 Series Engines

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Lockheed Model L-1011 series airplanes, that currently requires several modifications of the engine high speed gearboxes. This amendment requires that a new modification be installed in lieu of one of those previously required. This amendment is prompted by a report indicating that one of the currently required modifications is not completely effective because it can create interference problems between the fireloop and a fuel line. The actions specified by this AD are intended to reduce the possibility of a fire in the high speed gear boxes, and to ensure that any fire which may occur is readily detected by the flight crew.