Summary
We propose to adopt a new airworthiness directive (AD) for certain Airbus Model A300 B4-600 and A300 B4-600R series airplanes. This proposed AD was prompted by reports of cracks found in the bottom wing skin stringers at rib 14 during full-scale fatigue testing and in service. This proposed AD would require modifying the profile of stringer run-outs at rib 14 of both wings, including a high frequency eddy current inspection of the fastener holes for defects and repair if necessary. We are proposing this AD to prevent cracking in the bottom wing skin stringers, which could result in reduced structural integrity of the wings.