This proposal dedicated its tasks to the specification, design and development of a software application to support the CLEANSKY Green Regional Aircraft Design. The WEMACS software suite was intended to become a high-tech, flexible and innovative tool to provide estimation on structural components. Existing know-how on parts were used to provide accurate estimates on structural changes. The structures focus will be on the wings, fuselage pylons and tail of the aircraft. Parameters on size and geometry, weights and manufacturing costs shall be calculated with depth and accuracy. WEMACS shall obtain detailed weights for structural items taking baseline information previously obtained by conventional methods. It will also derive updated detailed information about costs to manufacture the aircraft. Knowledge Based Engineering (KBE) philosophy is where WEMACS draws its foundation. KBE is the added innovative component in WEMACS, driving progress in the technological implementation of the knowledge management vision and strategy for the aircraft engineering business.