Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This action requires a one-time inspection of the wiring and wire bundles of the aft main avionics rack (MAR) to determine if the wires are damaged, or riding or chafing on structure, clamps, braces, standoffs, or clips, and to detect damaged or out of alignment rubber cushions inserts of the wiring clamps; and corrective actions, if necessary. This amendment is prompted by an incident in which the automatic and manual cargo door test in the cockpit was inoperative during dispatch of the airplane, due to the wiring of the MAR chafing against clamps as a result of the wire bundles being installed improperly during production of the airplane. The actions specified in this AD are intended to ensure that the wires that route from the main wire bundles to the MAR and associated brackets, clamps, braces, standoffs, and clips are installed properly. Improper installation of such wiring and structure could cause chafing of the wire/wire bundles, which could result in electrical arcing, smoke, and possible fire in the MAR.