Summary
We propose to supersede airworthiness directive (AD) 2000-12- 11, that applies to certain Model A300 B4-600 and Model A300 B4-600R series airplanes. That AD currently requires repetitive 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. Since we issued that AD, we have determined through a fleet survey and an updated fatigue and damage tolerance analysis that the risk for fatigue cracking on the front and rear spar bottom booms is higher than was initially determined. This proposed AD would reduce the initial inspection compliance time and repetitive inspection interval. We are proposing this AD to detect and correct fatigue cracks in the bolt holes of the wing spars, which could result in reduced structural integrity of a wing spar.