Airworthiness Directives; McDonnell Douglas Model MD-10-10F, MD-10-30F, MD-11F, DC-10-10F, and DC-10-30F Airplanes

The FAA is adopting a new airworthiness directive (AD) for the McDonnell Douglas airplanes listed above. This AD requires identifying the part number of the cargo compartment smoke detectors and, if necessary, revising the Limitations section of the airplane flight manual to include procedures for testing the smoke detection system after the last engine is started. This AD also provides for the optional replacement of the subject smoke detectors with modified smoke detectors, which would terminate the operational limitation. This AD is prompted by a report indicating that the cargo smoke detectors can "lock up" during electrical power transfer from the auxiliary power unit to the engines. We are issuing this AD to identify and provide corrective action for a potentially inoperative smoke detector in the cargo compartment and ensure that the flightcrew is alerted in the event of a cargo compartment fire.