AIR 1939 provides guidelines in lieu of directives to achieve consistent Life Cycle Cost (LCC) analysis for military aircraft engines. AIR 1939 deals specifically with the direct Life Cycle Cost elements of Aerospace Propulsion Systems. It is recognized that propulsion is normally one part of a larger system, and that through its performance interaction with this overall system, propulsion can often exert a greater influence on system costs than are possible through changes in the direct propulsion system cost elements. AIR 1939 is not directed at this performance interaction issue. Instead, it provides a Life Cycle Cost approach which is a stand-alone measure of propulsion system cost - but which can also serve as a cost building block for broader system-oriented cost-benefit evaluations. AIR 1939 addresses communication of LCC data between equipment suppliers, aircraft engine producers, aircraft manufacturers, and users. The LCC data categories addressed include research, development, test and evaluation (RDT acquisition (initial procurement and investment); and operating and support (O
