Airworthiness Directives; Boeing Model 727 Airplanes

We are adopting a new airworthiness directive (AD) for certain Boeing Model 727 airplanes. This AD requires among other actions, installing new ground fault interrupter (GFI) relays for the main fuel tanks and the auxiliary fuel tank pumps. This AD also requires revising the FAA-approved maintenance program to incorporate new Airworthiness Limitations for the GFI of the boost pumps and for the uncommanded on system for the auxiliary fuel tank pumps. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent an electrical fault in the fuel pump system, which might cause a connector or end cap to burn through and a subsequent fire or explosion inside the fuel pump or wing spar area. We are also issuing this AD to prevent uncommanded operation of the auxiliary fuel tank pumps, which can cause them to run dry. This condition will increase pump temperature and could supply an ignition source to fumes in the fuel tank, which can result in a consequent fire or explosion.