Twenty years ago, the electronic valve gave way to the transistor; now the transistor as a discrete component has been replaced by the integrated circuit, and micro-processors are emerging as cheap, reliable and basic elements of electronic architecture.

Each step has yielded a major reduction in the size of equipment needed to achieve a particular function or to improve performance—but in spite of miniaturisation, an increasing volume of avionics has been incorporated into succeeding generations of aircraft as requirements for greater precision and safety have arisen.

Application has already provided striking improvements in the quality and ease of communication and navigation, which in turn have brought about the demise of the dedicated radio operator and navigator. The trend will continue with more automation of flight control and system management, leading to two-crew operation of most short and medium range aircraft—providing, of course, that the cost of ownership of additional equipment is less than the costs of the displaced crew member, and that flight safety standards continue to improve.