Airworthiness Directives; McDonnell Douglas Model DC-8 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-8 series airplanes, that currently requires a revision to the Airplane Flight Manual Supplement to ensure that the main deck cargo door is closed, latched, and locked; repetitive inspections of the wire bundle and door latch rollers to detect damage; and repair or replacement of damaged components. This amendment requires, among other actions, modification of the indication and hydraulic 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; the latching and locking mechanisms are not of adequate design to prevent structural deformation in the event of component jamming; and that there is an absence of a 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 the door, flight control, or severe structural damage.