Controversy continues to swirl around the FAA’s September 2005 regulations regarding aircraft thermal and acoustic insulation. The agency amended the original regulations after discovering the wording implicated a much broader range of components than intended and recognizing that in many cases compliant parts are not available. Subsequently the National Air Transportation Association has expressed concern relating to existing parts catalogs that continue to contain part numbers that do not comply with the new rule. While OEMs will ensure compliance of new production aircraft, parts catalogs of many out-of-production models have not been addressed by the rule, according to NATA. “Operators risk enforcement action for operating aircraft with noncompliant replacement insulation.”