This paper introduces a tool for preliminary system placement inside an aircraft’s fuselage. Objective is to estimate the effect of design decisions on system routing, which may then be used for better weight estimation or physical modeling. The method uses a detailed geometrical model of the fuselage including cabin and primary structure. The system components and connectors are placed according to knowledge patterns. The focus is on large fuselage systems such as the environmental control system, the water&waste
system and parts of the electrical system, which are the most significant in terms of size and weight
