Aluminum-Lithium Alloys

Airworthiness regulatory bodies are authorised and responsible for verifying and ensuring the safety and reliability of aircraft. There are many civil and military aviation organisations and regulatory bodies. The functions and responsibilities of several of these organizations are summarised in this chapter. Owing to the importance of aircraft structural fatigue, a survey of fatigue design philosophies is also given. This is followed by (i) a discussion of the airworthiness certification methodology for materials and structures, starting with the initial mill products and proceeding via incremental levels to the finished aircraft; and (ii) an example of material certification for an aluminium–lithium (Al-Li) alloy that is a candidate for use in the airframes of light combat aircraft (LCA).