On Aircraft Development : managing complex systems with long life cycles

Sammanfattning: Time plays an important role for the development of aircraft. The aircraft has a long life cycle and is composed of many systems with life cycles that sometimes differ with an order of magnitude in relation to the overall system. Aerospace and defense systems are subject to increasing systems of system integration, a globalized industry and in general more demand for change over its life.This thesis is based on clinical research. It combines experience from aerospace industry with general frameworks for product development such as: axiomatic design, the clockspeed framework and C-K theory. The purpose is to identify good development practice for future aerospace and defense systems development. The aircraft is here considered as a system with general properties such as high complexity with a long life and need for flexibility and integrity. Emphasis in the analysis is on time aspects.The life cycle is described for individual technologies as well as for the complex system. The development is analyzed in the dimensions of product, process and supply chain followed by a more general analysis. In the product dimension, axiomatic design is used to identify some ideal properties for a flexible system. The process dimension covers experiences and aspects on how to perform integrated product development, including identified success factors from experiences at Saab. In the supply chain dimension aspects of the supply chain for the actual type of systems are covered.The complex system is studied in its context. The coupling between the system flexibility and requirement stability is used to analyze properties of the system. It is pointed out that the system should be balanced such that domains of the system that are subject to stable requirements could be optimized and areas where requirements vary should be flexible and prepared for change. From this follows the need to have differentiated processes and supply chain strategies that supports the establishment of these properties in the system.The development capability is analyzed with focus on the extended enterprise, and the conditions in horizontal and vertical collaboration. In particular these aspects are studied based on Saab experiences for the possibility to combine the roles of being integrator, and supplier. The combination of different requirements for the two situations is addressed with a combination of core and interface processes in a so- called life buoy approach.Innovation is often highly constrained in the complex system context. The ideal system architecture proposed relaxes constraints for innovation. In addition, some properties of innovation in the complex system are discussed and in particular the application of demonstrators is discussed as a possible tool to orientate in an innovation intense environment.The thesis conclusions covers general aspects on how to balance between the three dimensions and how to decompose and differentiate such that it is possible to meet requirements with a strong need for optimization combined with requirements where there is a strong need to adapt over the life. Time considerations are found to support this decomposition and differentiation.