Impact of reliability of state-of-the-art electrical units on architecture of power supply system of modern aircraft

Airworthiness regulations require that the airliner should be proved to ensure passengers safety. The level of the aircraft system reliability is specified in Federal laws such as Code of Federal Regulations part 25. Electrical power system is very essential system because of providing energy for most functional systems for example such as flight control system, full authority digital engine controller, landing gear retraction system, and others. For providing safety conventional aircrafts have emergency electrical system which comprises ram air turbine, auxiliary power unit, batteries. This paper offers several architectures of power supply system without any special emergency systems. The required level of reliability is provided by state-of-the-art electrical units as permanent magnet generators or switched reluctance generators, power semiconductors, lithium-ion batteries. It allows to design simpler and lighter power system of airliner that will reduce cost of its design, certification, production and maintenance. The paper also concerns more-electric aircrafts.