Summary
The FAA proposes to supersede an existing airworthiness directive (AD) for certain McDonnell Douglas Model DC-8-70 and -70F series 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 proposed AD would add 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 proposed AD is prompted by the inadvertent omission of certain airplanes from the existing applicability. We are proposing 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.