Airworthiness Directives; McDonnell Douglas Model DC-9-10, -20, - 30, -40, and -50 Series Airplanes and C-9 (Military) Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) series airplanes, that requires visual and eddy current inspections to detect cracking of the frame-to-longeron attachment area, the frame-to- skin shear clips at certain fuselage stations, and the fuselage bulkhead at the front spar of the engine pylon in the aft fuselage; and repair, if necessary. This AD also requires certain modifications which, when accomplished, will terminate the requirement for inspections. This amendment is prompted by reports indicating that fatigue cracking has occurred at those areas. The actions specified by this AD are intended to prevent such fatigue cracking, which could cause damage to adjacent structure and result in reduced structural integrity of the airplane.