Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas airplane models. For certain airplanes, this proposal would require a one-time test to determine the material of the upper inboard spar cap of the wing, or a one-time inspection to determine if the slant panel cap has been repaired previously. For most airplanes, this proposal also would require a one-time inspection for corrosion of the slant panel cap of the wing leading edge assembly, and follow-on actions. This action is necessary to prevent stress corrosion cracking in the forward tang of the upper inboard spar cap of the wing, which could result in structural damage to adjacent components of the wing and consequent reduced structural integrity of the airplane. This action is intended to address the identified unsafe condition.