The secondary air system (SAS) has paramount impact on the safe operation, remaining service life and overall efficiency of aero engines. Due to the manifold interactions with other engine components, there is demand for effective consideration of the SAS in various processes along the engine life cycle. 1D fluid network models are the state of the art for modeling large SAS domains. They depend on the availability and accuracy of characteristics of the fluid network’s components and are considered as a low-fidelity tool when compared to the high-fidelity of 3D simulations, e. g. CFD or thermomechanical CSM. Since some SAS elements are very sensitive to changes in geometrical parameters or operation conditions, the widespread applicability of 1D models depends on an acceptable accuracy of the characteristics, which are build through experiments or high-fidelity simulations. For this reason, novel approaches are needed to combine 1D models with high-fidelity simulations in cost- and time-efficient ways. This paper contributes to this demand by pointing out, which sensitive components are challenging in 1D fluid network modeling and should particularly considered in high-fidelity simulations. It is presented, how the 1D and 3D models complement each other and what it is needed to combine them in so-called Multi-X simulations (multi-fidelity, multi-discipline, multi-physics...). Furthermore, it is shown how Multi-X simulations can be managed in a consistent way, for which an ontology based data model named simulation topology is one key feature. This is complemented by a data management system which, among other things, ensures the efficient handling of large amount of data.