Published online by Cambridge University Press: 27 October 2009
Near the Poles, the geographical system of reference by meridians and parallels approaches limiting conditions, and the apparent motion of heavenly bodies is unfamiliar. Accepted routines of navigation break down, and it is therefore necessary to devise new methods for the use of aircraft in polar regions. In addition, the weakness of the magnetic field in these regions forces us to modify or supplement the ordinary method of steering by magnetic compass. It cannot be too much emphasised, however, that the overriding criteria by which any technique must be examined are those which are common to navigation in all latitudes, and which are imposed by the nature of the aircraft itself. They arise chiefly owing to the speed and instability of the machine, and to the conditions of physical and mental strain in which the aerial navigator must work. Techniques and instruments must survive the three-fold test, applicable to any latitude: “Is the manipulative process handy enough to be done accurately by a navigator, tired or under nervous tension?”, “Is it simple enough for him to avoid errors under conditions of stress or mild anoxia?”, and “Is it fast enough?”
page 446 note 1 Sadler, D. H. Tables for astronomical polar navigation, Journal Institute of Navigation (London), Vol. 2, No. 1, 1949, p. 9–24Google Scholar, in which the presentation of tables for polar navigation is discussed, and in which a new series of star tables, H.O. 249, published by the United States Hydrographic Office, is mentioned. These have an entry by L.H.A. Aries for six chosen stars for each degree of latitude to 89°, and, though they were not available to the author at the time of writing, are likely to be preferred to the astronomical navigation tables (A.P. 1618) described above. They are reviewed in Journal Institute of Navigation (London), Vol. 1. No. 1, 1948, p. 97Google Scholar .
page 449 note 1 Herrick, S.Grid navigation. Geographical Review, Vol. 34, No. 3, 1944, p. 436–56CrossRefGoogle Scholar.
page 449 note 2 Tonta, L.A new type of polar chart. Hydrographic Review, Vol. 5, No, 2, 1928, p. 51–60Google Scholar, and, independently, Maclure, K. C. Polar navigation. (In Gatty, Harold. An investigation of the instruments and equipment required in celestial and dead reckoning polar aircraft navigation and their application. Washington, Bureau of Aeronautics, 1944, p. 187–200Google Scholar.) Originally produced in mimeographed form by R.C.A.F., Ottawa, 1941.