It is getting more and more important for an aircraft manufacturer to recognize the operators profit to achieve good products. The fuel system architecture of a long range aircraft with two engines has been used, to represent an example of the components needed to achieve the main functions required from a fuel system. System specific parameters such as price, weight, maintenance costs and power consumption have been used to evaluate the operating costs. A risk analysis tool has been used to evaluate the impact of uncertain input data on the system direct operating cost, using the monte carlo...