The European aviation industry is experiencing wide-ranging change including introduction of new technologies and operational concepts, while also facing demands for higher levels of safety performance. Existing approaches to gaining approval are often perceived as a barrier to adopting innovation and change; they can also miss significant interactions between parts of the system. The EC-funded ASCOS Project has developed a method and supporting tools to address these challenges. The ASCOS Method uses modular safety arguments to provide a framework to integrate existing approval approaches while also providing the flexibility to adapt the approaches where necessary to enable the smooth approval of advances in aviation technology.