Journal of Navigation

Research Article

Presidential Address: Navigation Aids to Aircraft All-weather Landing

Sir John Charnley CB

1. INTRODUCTION. In his Presidential address last year J. E. D. Williams treated us to a most absorbing, largely philosophical review of the development of the science of navigation over the last five centuries. In discussing the profound and enduring influence of radio waves on air navigation over the last century he commended as of ‘transcending importance’ the ‘homing quality’ of the radio beam in which the accuracy increases as distance from the transmitter decreases. He illustrated this ‘homing quality’ with references to the radio range for en-route navigation and the instrument landing system (ILS) for guidance to the runway. But he went further and remarked ‘Automatic landings in regular airline service are an example of how a perceived potential of the homing quality of radio has drawn to navigation a whole range of diverse applied sciences including, in this case, information theory, the properties of semi-conductors and the theory of servomechanisms and control, among many others.’