Abstract: Time-consuming manual in-situ visual inspections are a big challenge, in the manufacturing process of carbon fibre wing covers in aerospace industry. In the EU research project ZAero (Zero-defect manufacturing of composite parts in the aerospace industry) in-situ manual inspection on fibre placement stations thus shall be replaced by automatic inlineinspection. To quantify the improvements of the suggested process changes, experiment seriesperformed by a discrete event simulation (DES) model were needed to provide necessary keyperformance indicators (KPI). As the new inline inspection detects events and provides a lot ofadditional data for them, the simulation model proved to be very useful to support a decisionsupport system (DSS) to help decision makers in determining which of the events count as defectsand need to be reworked. In our work we show that a DES model, when proper implemented,is as versatile as a Swiss knife and can make valuable contributions to more than one life cycleof a manufacturing system.