Summary
This document proposes the supersedure of an exiting airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9-80 series airplanes and Model MD-88 airplanes, that currently requires an inspection to detect chafing of or damage to the wire bundle in the overhead switch panel of the cockpit, application of spiral wrap to the wire bundle, and corrective actions, if necessary. That AD was prompted by reports of chafed and shorted wires that resulted in smoke emanating from the overhead switch panel of the cockpit. This action would expand the applicability of the rule to include certain Model DC-9, C-9 (military), and MD-90-30 series airplanes. This action also proposes to add a requirement to reroute the wire bundle to preclude chafing and damage. The actions specified by the proposed AD are intended to prevent the potential for fire and uncontrolled smoke throughout the cockpit as a result of chafing and shorting in the electrical wire bundles.