AD FAA-2008-0637

The FAA is superseding an existing airworthiness directive (AD), which applies to all Lockheed Model L-1011 series airplanes. That AD currently requires an inspection of the fuel level control switch, the fuel level control switch wiring harness, and the wiring harness conduit for damage, wear or chafing, broken or missing O-rings, or indications of electrical arcing. That AD also requires replacement of a certain conduit in the fuel level control switch wiring harness, installation of electrical sleeving over the fuel level control switch wiring harness, and installation of the fuel level control switch that has been so modified. This new AD requires an inspection of the fuel level control switch, wiring harnesses, and harness conduit for any visible damage, wear or chafing, broken or missing O-rings, or indications of electrical arcing; an inspection to determine the part number of the wiring harness conduit; and corrective actions if necessary. This new AD also requires replacing certain sleeving with new, improved sleeving over the wiring harness of the fuel level control switch. This AD results from a design review of the fuel tank systems. We are issuing this AD to prevent chafing of the fuel level control switch wiring harness, which could cause arcing and result in a fire in the fuel tank.