Increasing traffic movements, size of aircraft and congestion of large buildings around modern civil airports, particularly those involved in major international operations, together with the predicted operation of STOL and VTOL types of aircraft, have led to an intensive review of the future needs for new approach and landing aids.

This paper was presented at an Institute meeting held in London on 15 December 1971, with Mr. H. E. Smith, Chairman of the Technical Committee, in the Chair. Mr. Wood, who is the United Kingdom member of the I.C.A.O. All Weather Operations Panel, reviews the whole situation broadly, with emphasis on operational requirements, present and future possibilities of the v.h.f./u.h.f. ILS guidance system and the effort, both national and international, to establish a new approach and landing guidance system which will satisfy future requirements.