The paper presents the importance of electricity parameters in transient states for assessing the ability of an aircraft's power grid to self-regulate. It has been shown that the quality of electrical energy of an aircraft's power system is influenced by its operating time. Aging changes resulting from long-term operation of the power system cause deterioration of electrical energy parameters, which directly affects airworthiness and flying safety. Maintaining standard energy parameters in transient states is very important to ensure proper operation of the aircraft. The article describes the method of measuring the quality of electricity in transient states, and using the example of the DC power system of the Su 22 aircraft, the essence of its network diagnostics in transient states is presented. Also presented are sample results of research conducted by the authors regarding changes in electrical energy parameters in transient states of the Su 22 aircraft, obtained during its many years of operation.