The airworthiness and reliability of aircraft electrical systems

Abstract

Standards for the airworthiness and reliability of electrical systems and equipment are discussed in relation to the overall standards for the aircraft and its engines, and the effect of duplication of systems and equipment is considered.The control and protection of generating systems is examined in relation to experience, particularly of total power failure, and it is concluded that systems have not proved sufficiently reliable in the past to justify entire reliance on them in aircraft which depend on electrical supply for their continued flight. Various methods of providing duplicate and emergency supplies are described.The electrical controls of engines and propellers is discussed in relation to engine reliability, and recommendations are made for improvement.Inadvertent operation of some services (e.g. control-surface trimmers, propeller reversing) may constitute a major hazard to the aircraft; a detailed assessment of the causes of such operation is made and of methods of avoiding it.In an aircraft which carries large quantities of fuel and uses other inflammable fluids at high pressures, the extensive use of electricity may involve a considerable risk of fire or explosion unless the most stringent precautions are taken. Some of the risks and the measures taken to combat them are described.