The evolution of airbus helicopters crashworthy composite airframes for transport helicopters

Abstract

Composite materials are nowadays widely used in helicopter airframe primary structures due to their specific inherent characteristics compared to conventional materials. The advantages of a design using composites compared to conventional designs (e.g. sheet/stringer in Aluminum) are for example a very competitive weight to volume ratio and an outstanding fatigue behavior. AIRBUS HELICOPTERS has a long history in designing composite airframes which imply crashworthy features to ensure a high level of protection for the occupants in case of a crash. This paper shows the history of the composite airframe developments in AIRBUS HELICOPTERS and its predecessors and presents an approach developed for new commercial transport H/C programs. Based on the experiences gained in previous research programs like the "BK117 Composite Airframe Program" and the ones gained in the development of the NH90, an approach has been developed to which extent the component requirements defined today in the relevant airworthiness regulations FAR/CS (e.g. emergency landing conditions general, emergency landing dynamic conditions, & fuel system crash resistance) will be implemented in future commercial HCs and how they will be complemented by an integrated system approach on airframe level in order to achieve AIRBUS HELICOPTERS in-house safety targets for the benefit of our customers. A smart trade-off between crash improvements and possible weight and cost penalties has to be conducted.