In order to assess the effects of bypass ratio on the cost and environmental per- formance of the civil aircraft with consideration of engine installation, a multidisciplinary analysis procedure was established, in which propulsion, geometry, aerodynamics, mass, mission per- formance, cost, noise and emissions analysis module were integrated. A typical wide body civil aircraft was used to illustrate the procedure, in which the cost and enviromental performance of wide body aircraft was analyzed with different engine bypass ratios ranging from 8 to 14. The results show that the civil aircraft with the highest bypass ratio engine achieves the lowest noise and landing-takeoff NOx emissions. However, the civil aircraft with the engine of moderate by- pass ratio （around 11） has the lowest cash operating cost and flight NOx emissions.
Journal of Aerospace Power