Airworthiness Directives; McDonnell Douglas Model DC-8-11, DC-8-12, DC-8-21, DC-8-31, DC-8-32, DC-8-33, DC-8-41, DC-8-42, and DC-8-43 Airplanes; DC-8-50 Series Airplanes; DC-8F-54 and DC-8F-55 Airplanes; DC-8-60 Series Airplanes; DC-8-60F Series Airplanes; DC-8-70 Series Airplanes; and DC-8-70F Series Airplanes

The FAA is superseding an existing airworthiness directive (AD), which applies to certain McDonnell Douglas transport category airplanes. That AD currently requires repetitive inspections for cracking of the lower cargo doorjamb corners, and corrective action if necessary. That AD provides for optional terminating action for certain repetitive inspections for certain airplanes. For certain other airplanes, that AD requires modification of the lower cargo doorjamb corners. This new AD adds airplanes to the applicability. The existing AD was prompted by reports of fatigue cracks in the fuselage skin in the lower cargo doorjamb corners; this AD is prompted by the inadvertent omission of certain airplanes from the existing applicability. We are issuing this AD to ensure that the unsafe condition will be addressed on all affected airplanes so that cracking in the lower cargo doorjamb corners is detected and corrected before it can result in rapid decompression of the fuselage and consequent reduced structural integrity of the airplane.