Airworthiness Directives; McDonnell Douglas Model DC-8-21, -31, -32, -33, -41, -42, and -43 Airplanes; and Model DC-8-50, -60, and -70 Series Airplanes; Modified per Supplemental Type Certificates SA1063SO, SA1862SO, or SA1832SO

This amendment adopts a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-8-21, -31, -32, - 33, -41, -42, and -43 airplanes; and certain Model DC-8-50, -60, and - 70 series airplanes; that have been converted from a passenger-to a cargo-carrying ("freighter") configuration. This action requires gaining access to the floor beam attachments to the lower door jamb within the main cargo door area; performing repetitive inspections to detect cracking or damage of such attachments, including splice plates, angles, and clips; and, if necessary, expanding the inspection area and replacing any cracked or damaged part with a new part. This action is necessary to prevent failure of such floor beam attachments during ground or flight operations, which could cause damage to the floor structure and consequent jamming of the flight control cables, and result in loss of controllability of the airplane in flight.