Summary
The FAA is revising an earlier proposed airworthiness directive (AD) for all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The original NPRM would have required an inspection for chafing of certain wire bundles located above the center fuel tank, corrective actions if necessary, and replacement of wire bundle clamps with new clamps. The original NPRM resulted from fuel system reviews conducted by the manufacturer. This action revises the original NPRM by adding an inspection for damage to the fuel vapor barrier area located below the wire bundles and corrective action, if necessary. We are proposing this supplemental NPRM to prevent chafed wire bundles near the center fuel tank, which could cause electrical arcing through the tank wall and ignition of fuel vapor in the fuel tank, and result in a fuel tank explosion.