A case study of a proxy composite aircraft duct assembly with built up surrounding structure compared to a monolithic aluminum design with surrounding cast structure. Advanced manufacturing techniques coupled with advanced material processes were used to develop a new duct design. The new aluminum design provides an alternative to the proxy composite assembly or older traditional built-up structural metallic designs.  The part and fastener count of the proxy composite duct structure was reduced while decreasing the recurring unit cost.  The new monolithic forged duct and cast superstructure utilizes high speed machining, friction stir welding of dissimilar product forms and cast aluminum technology for maximum part consolidation.