SOXO Air SIG S7 ILS, from Early Development to an Enduring World Standard

Frank B. Brady

Abstract:	The Instrument Landing System (KS) may set a record for major electronic system longevity. Stemming from early experiments dating back to 1919, it was developed into its present basic signal format in the middle 1930’s. It was well on its way to national standardization by the time of U.S. entry into WWII. At that time it was strictly a national system almost unknown outside of the United States. In January of 1944, the Aircraft Radio Laboratory at Wright Field, sponsored a mission to have the SCS-51 military ILS tested by the RAF and the 8th Air Force. The code name for the mission was SOXO AIR SIG S- 7. A small team and production ground and airborne equipment were sent to England for joint British- American trials. Tests were conducted at an RAF Flight Research airfield in central England. Although officially the tests lasted only a few months, the results were far reaching and had a major impact on the future of ILS. The tests gave large number of key aviation officials their first look at ILS, and as the program progressed, the ready availability of ground stations allowed operators both military and civil to become familiar with the system so that when postwar international conferences were held to select a landing system the ILS had a distinct advantage and was selected as the international standard. Challenged by microwave systems and radar talkdown systems in the early 1940’s and more recently by an internationally standardized Microwaw Landing System, the VHF-UHF ILS has surviwzd as the system of choice for civil operators and will certainly continue into the first quarter of the twenty-first century.
Published in:	Proceedings of the 48th Annual Meeting of The Institute of Navigation (1992) June 29 - 1, 1992 ANA Westin Hotel Dayton, OH
Pages:	457 - 464
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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