This handbook provides guidelines to perform the worst case analysis. It applies to all electrical and electronic equipment. This worst case analysis (WCA) method can also be applied at subsystem level to justify electrical interface specifications and design margins for equipment. It applies to all project phases where electrical interface requirements are established and circuit design is carried out. The worst case analysis is generally carried out when designing the circuit. For selected circuitry, worst case analysis (WCA) can be used to validate a conceptual design approach.