In practice there are different description mediums and software tools needed to implement a RAMS analysis (Reliability, Availability, Maintabiltiy, Safety). But with the help of Petri net models all four aspects will be assessed on only one model. But often the modeling of real systems by using simple Petri nets becomes very complex. A clear modelling of complex hierarchical Petri net models on one sheet is usually impossible. But with the use of a structured approach you have an effective benefit from the advantages of this mode of description.