MINIMIZING LIFE-CYCLE COST FOR SUBSONIC COMMERCIAL AIRCRAFT

The inclusion of life cycle cost (LCC) as early as possible in the conceptual design process is necessary because of the strong impact early design effort has on the total cost of an aircraft program. Considering LCC for military aircraft is the current industry standard; for commercial aircraft it is also necessary to weigh the merit of decreases in operating costs against increases in acquisition cost and vice versa. A methodology has been developed that makes it possible to identify an aircraft concept that will meet the mission requirements and have the lowest LCC. The methodology consists of an LCC module composed of elements to calculate RDT and E (research, development, testing, and evaluation) cost, production cost, DOC (direct operating cost), IOC (indirect operating cost), and an existing conceptual design and analysis code, the Flight Optimization System (FLOPS). The cost models chosen for the LCC module may produce questionable absolute cost estimates; however, the models chosen permit alternatives to be treated consistently so that relative comparisons are valid. Provision is made in the methodology for sensitivities to advanced technologies to also be investigated. The conceptual design system is applied to short-, medium-, and medium-to-long range subsonic commercial airplanes. The aircraft are optimized for minimum gross weight, fuel burned, acquisition cost, and DOC to show that different concepts result when LCC is considered. Sensitivities of the aircraft to economic and technology variables are illustrated. © 1989 American Institute of Aeronautics and Astronautics, Inc. All rights reserved.