The purpose of this research is to improve the approach for evaluating of new design solutions based on sensitivity analysis of takeoff mass (SFM) to initial changes in the basic project. The approach is based on the changes assessment in maximum takeoff mass of a developed project or an already existed basic variant of an aircraft with local design (project) changes, including the aerodynamic ones, that ensure the developing of a more advanced aircraft. In comparison with the existed known

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... oaches based on the mass growth factors, which were considered constant, the proposed approach takes into account more exactly the dependence of the takeoff mass on the initial local change in mass in terms of their functional purpose, as well as the aerodynamic characteristics. This approach allows the designer to calculate more precisely the final maximum takeoff mass changes in the early (preliminary) stages of conceptual design when looking for new design solutions. On numerical examples, carried out on the examples of transport category airplanes, a significant dependence of the wing aspect ratio influence on fuel efficiency is shown. The considered approach using SFM with semi-analytical aerodynamic analysis combination is simple, reliable and convenient in the analysis and synthesis of a new project for the design process based on the base variant.