The paper explores the application of topology and parametric optimization methods for the modernization of helicopter transmission components to reduce their weight. Examples of optimization design for gears, carriers, gearbox housings are considered. The importance of optimization direction development in helicopter transmission design is substantiated, because optimization is the most effective direction for helicopter weight reduction. Different formulations of optimization problems are analyzed, considering the specific working conditions of aviation gear wheels and shafts, as well as examples of housing part optimizations. The efficiency of topology and parametric optimization is compared, and an approach to their joint use as the most promising way to improve the design of aircraft transmission parts is proposed.