Airworthiness Directives; McDonnell Douglas Model DC-8-55, DC-8F-54, and DC-8F-55 Airplanes; and Model DC-8-60, DC-8-70, DC-8-60F, and DC-8-70F Series Airplanes

The FAA is superseding an existing airworthiness directive (AD) that applies to certain McDonnell Douglas Model DC-8-55, DC-8F-54, and DC-8F-55 airplanes; and Model DC-8-60, DC-8-70, DC-8-60F, and DC-8- 70F series airplanes. The existing AD currently requires a one-time inspection for previous repairs of the aft fuselage skin panel at the longeron 28 skin splice, repetitive inspections for cracks of the same area, and related investigative and corrective actions. The existing AD also provides optional actions for extending the repetitive inspection intervals. This new AD re-defines and more clearly describes the optional actions for extending the repetitive inspection intervals. This AD results from our determination that the inspections and actions described in the existing AD do not adequately address the unsafe condition. We are issuing this AD to detect and correct cracks in the aft fuselage skin at the longeron 28 skin splice, which could lead to loss of structural integrity of the aft fuselage, resulting in rapid decompression of the airplane.