Summary
We are revising an earlier proposed airworthiness directive (AD) for the products listed above. That NPRM proposed a one-time inspection to detect damage of the wire assemblies of the tail tank fuel system, a wiring change, and corrective actions if necessary. That NPRM was prompted by fuel system reviews conducted by the manufacturer. This action revises that NPRM by adding, for certain airplanes, a general visual inspection for correct installation of the self- adhering, high-temperature electrical insulation tape; installation of a wire assembly support bracket and routing wire assembly; changing wire supports; and installation of a wire protection bracket. We are proposing this supplemental NPRM to detect and correct a potential of ignition sources inside fuel tanks, which, in combination with flammable vapors, could result in a fuel tank fire or explosion, and consequent loss of the airplane.