Federal Aviation Administration January 24, 2005 – Federal Register Recent Federal Regulation Documents

The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. This proposed AD would require repetitive general visual inspections for dirt, debris, and drain blockage and cleaning of the aft fairing cavities of the engine struts; and modification of the aft fairings, which would terminate the repetitive general visual inspections. This proposed AD is prompted by a report indicating that water had accumulated in the cavities of the engine strut aft fairings. We are proposing this AD to prevent drain blockage by debris that, when combined with leaking, flammable fluid lines passing through the engine strut aft fairing, could allow flammable fluids to build up in the cavity of the aft fairing, and consequently could be ignited by the engine exhaust nozzle located below the engine strut, resulting in an explosion or uncontrolled fire.

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.