26th INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES MULTI-OBJECTIVE AIRCRAFT OPTIMIZATION FOR MINIMUM COST AND EMISSIONS OVER SPECIFIC ROUTE NETWORKS

Historically, maximizing profits for corporate shareholders has been the primary goal for aircraft designers. Due to climate change concerns, environmental performance is quickly becoming a major design focus. A methodology to design one or more aircraft to satisfy demand on a given route network is described. The objectives are to minimize direct operating costs, CO2 emissions and NOX emissions. A hierarchical decomposition is used with discipline-specific optimization algorithms. A modified version of the NSGA-II multi-objective genetic algorithm is implemented in the system level aircraft design subspace. The CPLEX integer solver is used in the fleet assignment subspace. Results are presented for a test problem that involves designing a single aisle commercial aircraft for a route network consisting of 4 cities and 8 route segments. A Pareto front is found and the characteristics of the optimal aircraft designs and fleet assignment solutions are examined. The results show a definitive trades between operating costs and NOX emissions and CO2 emissions and NOX emissions. Operating costs and CO2 emissions are strongly related, with little if any trade off evident. All designs show benefits from using higher bypass ratio engines and thicker, higher aspect ratio wings than today’s single aisle commercial aircraft.