Life Cycle Cost (LCC) analysis forms a vital input to the design of cost effective aerospace propulsion systems. By necessity, LCC analysis requires extensive communication between a large range of participants in a given program: customer, aircraft manufacturer, engine producer, equipment suppliers, and across professional disciplines within each of these organisations. This paper presents an overview of ARP 4294, “Data Formats and Practices for Life Cycle Cost Information”, which provides a range of specific data formats and recommended practices to support these communications. ARP4294 is primarily directed at the LCC of military propulsion systems. Consistency and understanding of information exchanged are promoted as are the role and responsibilities of participants at each phase of the program. ARP 4294 supplements the general guidelines of AIR 1939 and complements ARP 4293.