After an initial evaluation of the carbon fibres and matrix resins available at the time (1968) Hawker Siddeley Aviation embarked, under the sponsorship of the then Ministry of Technology, on the design and development of a number of representative aircraft structural components in order to gain experience of the overall problems involved and to give a lead in determining the direction of the necessary materials and process development programmes. An essential feature of this work was that the components produced should be cleared for extended flight trials so that not only would a good deal of useful service experience be gained but also many principles of quality and process control would be established and a platform for discussions with the various official bodies would be provided. In addition, by using the normal shop facilities for the manufacture of the components, it was hoped to introduce as many company personnel as possible to the new material.