Summary
We propose to supersede Airworthiness Directive (AD) 2011-09- 04, which applies to all Lockheed Martin Corporation/Lockheed Martin Aeronautics Company Model 382, 382B, 382E, 382F, and 382G airplanes. AD 2011-09-04 currently requires repetitive inspections for any damage of the lower surface of the center wing box, and corrective actions if necessary. Since we issued AD 2011-09-04, an evaluation by the design approval holder (DAH) indicated that the center wing box is subject to widespread fatigue damage (WFD). This proposed AD would also require replacement of the center wing box, which would terminate the repetitive inspections. This proposed AD would also add a concurrent related investigative action. We are proposing this AD to detect and correct fatigue cracking of the lower surface of the center wing box, which could result in structural failure of the wings.