With the development of More Electric Aircraft (MEA), novel power distribution systems (PDSs) are required to meet significantly increased electrical load demands onboard. Nevertheless, newer designs must comply with the strict flight operational and safety requirements, while achieving optimisation aims, such as reducing aircraft weight and energy consumption. This paper proposes a two-stage optimisation design method for a novel PDS investigated for MEA. Two optimal power scheduling-based models for minimising power losses and PDS weight are formulated in Mixed-Integer Linear Programming (MILP). The first model considers varying load demands and is solved for all flight stages simultaneously in the first design stage for weight minimisation. The obtained architecture is further optimised for all faulty scenarios and selected typical fight stages simultaneously in the second design stage to improve the PDS reliability. Consequently, a low power loss, light weighted, and fault-tolerant PDS architecture is obtained. A case study is provided to exemplify the improvement in the PDS by adopting the proposed method.