Formal systems engineering processes are often used in the design, implementation and testing of the software used in these safety-critical control systems. This requirement led to the development and use of specialized software such as model-based systems engineering (MBSE) tools. The application development toolset SCADE (from Esterel Technologies) (not to be confused with the application category SCADA) is an example of an MBSE tool and has been used as part of the development of FADEC systems.