This category includes the cost of feasibility (trade) studies; system analyses (support concept development); detailed design and development (including software); fabrication, assembly, and test of engineering models; initial system testing and evaluation; and associated documentation. The cost attributable to maintainability at this stage is relatively high. Depending upon system complexity, the maintainability engineer may need to implement design approaches that could easily account for 10% of the development costs, especially if extensive BIT and diagnostics are involved, to meet the maintainability requirements. Remember, however, that investments in maintainability made early in a program can significantly reduce downstream operation and maintenance costs. The goal during research and development should be to make investments that will reduce the life cycle costs to the lowest possible value.
The design approaches recommended by the maintainability engineer must be based upon the customer's requirements, the operational environment, experience, field surveys and interviews, and trade studies.