Summary
We propose to adopt a new airworthiness directive (AD) for all Airbus Model A321 series airplanes. This proposed AD was prompted by a determination from fatigue testing on the Model A321 airframe that cracks could develop in the cabin floor beam junction at certain fuselage frame locations. This proposed AD would require repetitive inspections for cracking in the cabin floor beam junction at certain fuselage frame locations, and repair if necessary. We are proposing this AD to address the unsafe condition on these products.