Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9 and C-9 (military) series airplanes. This proposal would require 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 proposal also would require certain modifications, which, when accomplished, would terminate the requirement for inspections. This proposal is prompted by reports indicating that fatigue cracking has occurred at those areas. The actions specified by the proposed AD are intended to prevent such fatigue cracking, which could cause damage to adjacent structure and result in reduced structural integrity of the airplane.