Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Boeing Model 737-100, - 200, -300, -400, and -500 series airplanes, that currently requires removal of the fuel boost pump wiring in the conduits of the wing and center fuel tanks; an inspection to detect damage of the wiring, and corrective action, if necessary; and eventual installation of Teflon sleeving over the electrical cable. This action would expand the inspection requirement to include additional airplanes, add repetitive inspections for all airplanes, and reidentify the requirement to install Teflon sleeving as a nonterminating action. This proposal is prompted by the FAA's determination that Model 737-100 through -500 series airplanes that are not affected by the current AD must also be protected against excessive wire chafing of the fuel boost pump wiring and that all affected airplanes must be repetitively inspected. The actions specified by the proposed AD are intended to detect and correct chafing and prevent electrical arcing between the fuel boost pump wiring and the surrounding conduit, which could result in arc-through of the conduit, and consequent fire or explosion of the fuel tank.