Airworthiness Directives; Boeing Model 737-100, -200, -300, -400, and -500 Series Airplanes

This amendment supersedes 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 amendment expands the inspection requirement to include airplanes with fewer than 20,000 flight hours; requires additional repetitive inspections for all airplanes; reidentifies the requirement to install Teflon sleeving as a nonterminating action; and removes the requirement to report inspection results. This amendment 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 Model 737-100 through -500 series airplanes must be repetitively inspected. The actions specified by this 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.