Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas DC-10 and KC-10 series airplanes. This proposal would require repetitive eddy current inspections to detect fatigue cracking of the pylon aft bulkhead flange, upper pylon box web, fitting radius, and adjacent tangent areas; and repair, if necessary. This proposal is prompted by fatigue cracking found in the wing pylon aft bulkheads on two airplanes. The actions specified by the proposed AD are intended to prevent failure of the wing pylon aft bulkhead due to fatigue cracking, which could lead to separation of the engine and pylon from the airplane.