My title is deliberately rather similar to that of Jed Williams' book because it was from his erudite and comprehensive work that I drew my inspiration. There are many volumes dealing with radio navaid engineering development but few, if any, about the very real and practical problems faced by navigators of interpreting, sometimes under very difficult circumstances, what they presented. Very few navigators of the 40s and 50s were expert draughtsman or academicians with degrees in mathematics or electronics, yet they were expected to comprehend and apply concepts that a few years earlier would have earned them such degrees. These fundamental problems of interpretation also seem to have been rather lost on some of those who were responsible for choosing which radio navaids to install. I have terminated my survey at the ‘steam’ era, rather than going all the way to ‘satellites’, not only because we have heard so much of satellites lately that it is time to give them a rest, but also because it was computers — the ‘ steam’ of navaids — that got us into the modern age of automated navaids when interpretation became far easier and the need for specialists doing little else vanished. My own experience is that of an aerial navigator so I hope our marine and land-based members will not object if I confine my remarks to aviation.

Part I of this chapter was included in the January 1997 issue of the Journal, Vol. 50, p. 65.

The Smith Brothers, 1919. Captain Ross M. Smith, of the Australian Flying Corps based in Palestine, flew a Handley Page 0/400 late in 1918 on a special flight to Baghdad and beyond, carrying as passenger Major General W. G. H. Salmond, the RAF's Middle East Commander. Flying as co-pilot was Brigadier-General Borton, Commander of the Palestine Brigade. Smith had been flying, in support of Lawrence's forces, another 0/00 which Borton had brought from England.

This paper is the sixth chapter of a series on the history of air navigation systems which have appeared from time to time in the pages of the Journal since 1988. Part II of this chapter will appear in the next issue of the Journal.

The author acknowledges the assistance of Bath College of Higher Education and, in particular, Dr Terence Rodgers, The Royal Aeronautical Society, The Royal Air Force Museum, and Philip Saxon of the Royal Air Force Historical Society.

Today, no single technology has more broad-reaching potential for worldwide civil aviation than the future applications of satellite technology. These applications represent the greatest opportunity to enhance aviation system capacity, efficiency and safety since the introduction of radio-based navigation systems more than 50 years ago. The foundation for this optimism is the Global Positioning System (GPS), a satellite-based radio navigation system operated and controlled by the United States Department of Defense (DoD). In December 1993, DoD declared GPS to be in initial operational capability (10c), which means 24 satellites are now in orbit, available and usable for satellite navigation. The Federal Aviation Agency (FAA) responded to this potential through initiation of a comprehensive satellite programme involving government, industry and users to expedite research, development and field implementation of satellite-based navigation services.

This paper is the fifth chapter of a series on the history of air navigation systems. Comments on the content of the paper would be welcomed by the author and the editor.

This paper is the third chapter of a series on Air Navigation Systems during the period from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. Some initial comments on the paper are included in the Forum section of this issue of the Journal. Further comments would be welcomed by the author and the editor.

This paper is the second chapter of a series on Air Navigation Systems during the fifty years from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. These papers are intended as critical commentaries. A definitive history has yet to be written. The writer would be grateful to receive criticisms of the paper or comments on the subject.