Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model MD-11 series airplanes. This proposal would require a one-time inspection to detect riding, chafing, or damage of the wire bundles adjacent to the disconnect panel bracket of the observer's station. The proposed AD also would require repair or replacement of damaged wires with new or serviceable wires; installation of anti-chafing sleeving on the wire bundles, if necessary; and installation of grommet along the entire upper aft edge of the disconnect panel bracket. This proposal is prompted by a report indicating that the circuit breakers tripped on a Model MD-11 series airplane due to inflight arcing behind the avionics circuit breaker panel as a result of chafing of the wire bundles adjacent to the disconnect panel bracket assembly. The actions specified by the proposed AD are intended to detect and correct such chafing, which could result in a fire in the wire bundles and smoke in the cockpit.