Summary
We propose to supersede Airworthiness Directive (AD) 2011-09- 03, which applies to all Lockheed Martin Corporation/Lockheed Martin Aeronautics Company Model 382, 382B, 382E, 382F, and 382G airplanes. AD 2011-09-03 currently requires repetitive eddy current inspections to detect cracks in the center wing upper and lower rainbow fittings, and corrective actions if necessary; and repetitive replacement of rainbow fittings, which would extend the repetitive interval for the next inspection. Since we issued AD 2011-09-03, analysis of in-service cracking has shown that a reduction in the inspection intervals is necessary for the upper rainbow fittings. This proposed AD is intended to complete certain mandated programs intended to support the airplane reaching its limit of validity (LOV) of the engineering data that support the established structural maintenance program. This proposed AD would require reduced intervals for inspections of the upper rainbow fittings. We are proposing this AD to detect and correct fatigue cracking of the upper and lower rainbow fittings on the center wings, which could grow large and lead to the failure of the fitting and a catastrophic failure of the center wing.