Summary
We propose to adopt a new airworthiness directive (AD) for all Model 382, 382B, 382E, 382F, and 382G airplanes. This proposed AD would require repetitive eddy current inspections to detect cracks in the center wing upper and lower rainbow fittings, and corrective actions if necessary; and repetitive replacements of rainbow fittings, which would extend the repetitive interval for the next inspection. This proposed AD results from a report of fatigue cracking of the wing upper and lower rainbow fittings during durability testing and on in-service airplanes. Analysis of in-service cracking has shown that these rainbow fittings are susceptible to multiple site fatigue damage. We are proposing this AD to detect and correct such fatigue cracks, which could grow large and lead to the failure of the fitting and a catastrophic failure of the center wing.