Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas transport category airplanes. For certain airplanes, this proposal would require a general visual inspection to detect cracking in the nuts on the lower attach bolt assemblies of the forward attach bracket of the inboard flap outboard hinge, replacement of both upper and lower attach bolt assemblies with new bolts and nuts made from Inconel material, and replacement of certain preload-indicating (PLI) washers with new washers. For certain other airplanes, this proposal would require replacement of the lower attach bolt assemblies of the inboard forward attach bracket of the inboard flap outboard hinge with new bolts and nuts made from Inconel material, and replacement of PLI washers with new washers. These actions are necessary to prevent separation of the inboard flap outboard hinge from the wing structure and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.