Aircraft Precison Landing Guidance and Related Safety Issues

Richard H. McFarland

Abstract:	Land/marine navigation is usually thought of in the horizontal sense. With air navigation there is another component in involving the third dimension which is usually the more difficult to accomplish. This paper identifies the various problems and points to the contemporary means of obtaining solutions. These are all related to what is generally called precision landing guidance. Research indicates that in many instances it is the absence of this vertical component of navigation that is a strong contributor to aircraft accidents. The Korean Airlines crash in Guam in August, 1997 is a recent, prime example. There are several means available for obtaining vertical navigation. V-Nav from area navigation is available, but the emphasis is on guidance available from ILS, and GPS. Predictions for future uses of those are presented along with the practicalities. The term, precision landing guidance, is used in aviation parlance to denote that vertical guidance is provided in addition to the horizontal component. In this paper the usual definition of precision is also discussed as it relates to what accuracies and resolution must be provided the aviator for safe operation of the aircraft. As the aircraft descends to lower and lower altitudes above ground with radio navigation, the true precision of the guidance signal must be greater. Safety is paramount; when considering air navigation information, per se, absence can derogate safety. Issues concerning quality of landing guidance information versus non-availability are addressed. The present practice of removing systems from service or otherwise making then unavailable is challenged. Responsible and greater use of flight simulation is suggested as means for defining, in the context of air safety, more appropriate quality assessments and limits for guidance signals.
Published in:	Proceedings of the 1998 National Technical Meeting of The Institute of Navigation January 21 - 23, 1998 Westin Long Beach Hotel Long Beach, CA
Pages:	255 - 262
Cite this article:	McFarland, Richard H., "Aircraft Precison Landing Guidance and Related Safety Issues," Proceedings of the 1998 National Technical Meeting of The Institute of Navigation, Long Beach, CA, January 1998, pp. 255-262.
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