Maintenance of electric equipment in modern aircraft

IN INTRODUCING the subject of electrical maintenance in modern aircraft, it is felt that a brief history of the development of these systems is in order to show the development from the rather simple systems as used on the DC-2's and DC-3's, which were the latest design 10 to 12 years ago, to the complex maintenance required on the intricate electric systems used in the modern airplanes such as Constellations, Martin 404's, and so forth.