Summary
The FAA is revising an earlier NPRM for an airworthiness directive (AD) that applies to certain Airbus Model A330 airplanes and Model A340-200 and -300 series airplanes. The original NPRM would have required repetitive detailed inspections for cracking in the aft web of support rib 6 between certain bottom skin stringers on both wings; high frequency eddy current inspections for cracking of the attachment holes of the fuel pipes, and repair if necessary. The original NPRM also would have provided for an optional modification, which would extend a certain inspection threshold. The original NPRM resulted from a report of significant cracking found in the aft web of support rib 6 on both wings. This action revises the original NPRM by mandating, for certain airplanes, a new modification of support rib 6 on both wings, which would end the repetitive inspection requirement. This action also reduces the applicability in the original NPRM. We are proposing this supplemental NPRM to prevent cracking in the aft web of support rib 6, which could result in overloading of adjacent ribs and the surrounding wing structure and consequent reduced structural integrity of the wing.