The basis for this Technical Note (TN) are the physical descriptions of the MATLAB/Simulink Functional Model Library of the Environmental Control System – FLECS (see FLECS_WT3.1_3.3_3.4_TN, https://doi.org/10.48441/4427.2052). In this TN, larger units (pack, cabin, controller, vapor compression cycle system) of the Environmental Control System (ECS) are constructed from the elementary components. Finally, the complete ECS of a passenger aircraft is modeled. The various basic air conditioning systems that were built with FLECS are tested for stability and real-time capability. In addition, various system configurations are validated using measurement data from aircraft or examples from the literature.