Summary
We propose to supersede Airworthiness Directive (AD) 97-07-14, for certain Airbus Model A320-111, -211, and -231 airplanes. AD 97-07- 14 currently requires modification of an area on the front spar of the wing center section by installing shims and new fasteners to reinforce pressure floor fittings. Since we issued AD 97-07-14, we have determined the need for repetitive inspections on airplanes on which the modification of the rib flange on the front spar of the wing center section has been done. This proposed AD would continue to require modifying the rib flange on the front spar of the wing center section by installing shims and new fasteners to reinforce pressure floor fittings; and would require repetitive high frequency eddy current inspections for cracking of the radius of the rib flanges and vertical stiffener at frame 36, a rototest inspection for cracking of the fastener holes of the rib flanges, repair if needed, and adding additional airplanes to the applicability.We are proposing this AD to prevent fatigue cracking on the rib flange area of the front spar of the wing center section, which can reduce the structural integrity of fuselage frame 36 and the wing center section.