**2.5 Large autoclaves**

One enabling capability that supports the evolution of the current state-ofpractice for composite fuselage manufacturing is large autoclaves. There are many, many, many, many research and historical, ongoing and planned for the future, development efforts focused on OOA (or non-autoclave as it was called in the 1980s) materials and processes with the goal of eliminating that monument, the autoclave. The goal is noble (and not new) and the development efforts are making great progress and will, someday in the future, represent a significant (if not all) portion of the composite structure on commercial passenger aircraft—just not today. We already see components made from liquid molding processes being used in specific applications and families of parts and components on aircraft like the 787 and A350, just not the primary fuselage panels and stringers—yet. The maturity, forgiving nature, and low risk of baseline autoclave cured systems made it an easy decision for programs like the 787 and A350 to progress knowing that it was just time and money required to build autoclaves large enough to meet the needs of the program. No new technology needed, just scale and incorporation of improvements being realized by the autoclave industry, such as control systems and operational efficiencies. Spirit even built their own liquid nitrogen generating plant onsite to service their large autoclaves (**Figure 22**).
