To make a long story short, after exhaustive and profound discussions it was agreed that:
b. Standard LORAN; grid
c. Low frequency (LF) LORAN
land-line direct telephone lines should be the primary means to provide for direct controller-to-controller voice communications in the air traffic control services. With regard to the designation of the VOR as standard aid, it is to be noted that, until 1954, this decision led to very engaged discussions. As of 1946,the United Kingdom, while world-widely subscribing to a point-source navigation aid providing bearing and distance, maintained that there was a special requirement for a short-range navigation aid in Europe providing area coverage. In their view this was essential because of the particularly dense criss-cross pattern of potential air routes in Europe which resulted from the many population centres distributed nearly evenly throughout Europe and which, when served by point-source aids, would impose inordinate high economic demands on States, quite apart from possible technical (frequency assignment, siting) difficulties. The UK therefore originally proposed the GEE system and later the DECCA system as a supplementary navigation aid for Europe. For a number of reasons, not the least being that, at that time, an area system could only be realised with reference to a hyperbolic grid system, this proposal was not adopted.
the concept that a safe, orderly and expeditious flow of air traffic could only be maintained by air traffic control if flights were routed along prescribed airways (corridors of a specified width, normally 10 NM, and covering all altitudes normally used by civil air transport operations) between their point of departure and their destination. When following these airways, flights would be controlled throughout their progression and be provided with clearances ensuring a collision-free flight path. This concept was based on experience gained in North America where air traffic densities had reached dimensions which, at certain locations, were vastly superior to those observed in Europe at that time; and
the concept that air traffic control should be restricted to specified portions of the airspace around major airports only, while otherwise leaving it to pilots to plan and fly their own route except that information on the progress of other flights would be provided if the danger of a collision was likely. This concept was based on the assumption that channelling of air traffic into comparatively narrow corridors was: in fact, increasing the danger of collision while this was reduced when pilots chose their own route, thus obtaining a much more random distribution of traffic.
After prolonged and very engaged discussions (and a number of Close "encounters" between flights in "free flight areas"), the airway concept was finally adopted and a basic European airways network was developed.
In the field of air-ground communications, originally only 4 VHF channels were available (118.1 MHz for towers, 119.7 MHz for approach purposes, 122.1 MHz for area control and 121.5 MHz for emergencies) and these had in addition to be shared with the military. By 1952, the situation had therefore become somewhat "crowded" and it was found necessary to take corrective measures. It was for this reason that, in November 1952, a special frequency assignment meeting was held in the Paris Office which prepared a new plan for the assignment of frequencies to ATC facilities serving international air navigation operations based on the repetitive use of 19 VHF channels throughout the EUR Region.
In March 1952, France, as the host States of the European Office invited ICAO to convene the 3rd European-Mediterranean Regional Air Navigation Meeting in Paris and this turned out to be one of the biggest meetings that had so far been organised by ICAO. Some 350 representatives of more than 60 States were present and in 4 weeks of often hectic work it was possible to develop a Regional Plan covering all aspects of air navigation from aerodromes to search and rescue which were required to cater for international flight operations in the next 5-8 years. Refinements to this plan, especially as regards the ATS route Network and ATC air-ground communications were developed in two subsequent meetings in the Paris Office in the same year so that, by the end of 1952, a complete internationally agreed project for the development of international air navigation in a major area of the world was available.
Activities of the European Office up to 1954 - NAT Region
The major problem in the North Atlantic Region which was of concern to the Paris Regional Office at that time was that related to communications. Both, ground-ground and air-ground communications were mainly conducted via high frequency (HF) channels with all the technical and procedural problems that are inherent to this means of communication. Selection, attribution, assignment and specification of the particular operating mode and time for each available HF channel constituted the main task because all this required careful co-ordination between the operating stations on the ground that operated in a network configuration and with airline operators.