Airworthiness Directives; McDonnell Douglas Model DC-8 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-8 series airplanes that have been converted from a passenger to a cargo-carrying ("freighter") configuration, that requires a revision to the Airplane Flight Manual Supplement to ensure that the main deck cargo door is closed, latched, and locked; inspection of the door wire bundle to detect discrepancies and repair or replacement of discrepant parts. This amendment also requires, among other actions, modification of the hydraulic and indication systems of the main deck cargo door, and installation of a means to prevent pressurization to an unsafe level if the main deck cargo door is not closed, latched, and locked. This amendment is prompted by the FAA's determination that certain main deck cargo door systems do not provide an adequate level of safety, and that there is no means to prevent pressurization to an unsafe level if the main deck cargo door is not closed, latched, and locked. The actions specified by this AD are intended to prevent opening of the cargo door while the airplane is in flight, and consequent rapid decompression of the airplane including possible loss of flight control or severe structural damage.