Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Airbus Model A300- 600 series airplanes, that currently requires repetitive ultrasonic inspections to detect cracks in the bolt holes inboard and outboard of rib 9 on the bottom booms of the front and rear wing spars, and repair, if necessary. This action would revise the compliance thresholds for the inspection and would require that the inspections be repeated at reduced intervals. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent fatigue cracks in the bolt holes of the wing spars, which could result in reduced structural integrity of a wing spar.