Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-8 series airplanes. This proposal would require a one-time eddy current conductivity test to determine the material type of the lower cap of the wing front spar; and modification of the lower cap of the wing front spar, if necessary. This proposal is prompted by reports of stress corrosion cracking in the forward tang of the lower caps of the wing front spar. The actions specified by the proposed AD are intended to prevent such stress corrosion cracking, which if not corrected, could result in reduced structural integrity of the wing.