History: Activities of the European Office from 1965 to 1971

EUR Region

The developments in the EUR Region, as described previously, made it necessary to convene in 1966 a further, the fifth, Regional Air Navigation Meeting in order to try and bring the Regional Plan as a whole up to date and include therein the foreseeable future requirements. The large attendance (and the first participation by observers from States of the Central and Eastern parts of the EUR Region) together with the growing complexity of the planning machinery showed again, as already in 1958, that the method of achieving this in one single four -weeks meeting was hardly adequate, despite the efforts of all participants involved.

Primary reasons for this were:

1. traffic predictions were becoming more and more difficult since peak traffic periods, to which the air navigation system was to respond were largely caused by charter operations during the summer holiday season and a representative organisation of charter operators comparable to that of the scheduled airlines (IATA) did not exist;

2. the technical equipment required to allow ground services to increase its traffic handling capacity was becoming not only more complex, thus requiring longer "lead-times" for its installation but ' because of the rapid technical progress, especially in the field of electronics, was also subject to frequent modifications to reflect latest technology with the inevitable changes in cost, and
3. because of the increased use of automation in such equipment, the question of compatibility of such equipment in adjacent facilities, provided by different States, gained more and more importance.
Boeing's 747 launched the wide-body age

Despite these additional difficulties, the 1966 Meeting succeeded in preparing a new Regional Plan, however with the proviso that its parts dealing with the air traffic and the communication services would require close observation in order to make necessary adjustments when this was required by circumstances. That this was a justified precaution, was born out by the fact that, already in 1968 it was necessary to hold a special meeting in order to make a complete review of the plan for VHF air-ground communications in the Region and, one year later, a further special meeting dealing again with communications and air traffic services (mainly radio navigation aids, use of secondary surveillance radar (SSR) and ground-ground communications between ATS units). 

It is obvious that the preparation, conduct and follow-up of these meetings presented a formidable challenge to the Paris Office, not only from the point of view of sheer workload but also from that of consolidation-- of national requirements because the air traffic services and communications part of the Regional Plan assumed more and more the character of integrated regional systems rather than the accumulation of a number of independent national systems with more or less loose connections. It should also be mentioned that, as regards this consolidation task, the first beneficial effects of Eurocontrol's work became apparent, even though this new organization still had its own particular difficulties to cope with.

In any case, by about 1970, it was evident that, if the air navigation system in the EUR Region was to keep pace with the growing demands imposed on it, it was necessary to provide for a continuous international planning machinery which conducted planning on a regional scale, based on reliable information regarding expected demands on such a system.

Operational and technical aspects, supporting this contention were:

1. the growing amount of delays which were experienced by operators in Europe, especially during the critical week-end periods of the summer season because the air traffic control system was, at certain, internationally critical points overloaded and has therefore to resort to restrictions in the acceptance of air traffic. One side-effect of this situation, illustrating the interdependence of the ATS system on a scale occasionally even extending beyond the EUR Region, was that these artificially imposed limitations on the flow of air traffic affected areas where the locally generated air traffic itself could have been handled without difficulties. (To illustrate this in an extreme example, it occurred that flights from East Africa to major airports in Europe had to wait up to 2 or 3 hours on the ground in Nairobi before they could be accepted in the European traffic flow some 4 or 5 hours later);


2. the lack of reasonably reliable forecasts regarding traffic developments, either in a general manner or in detail, related to specific routes, days and/ or times of the day; and

3. the complete lack of an agreed method or methods permitting to assess, within reasonable tolerances, the likely traffic handling capacity of an ATC unit under specified circumstances so as to serve as an important planning factor.

This, together with a lack of agreed methods for the formulation, promulgation, distribution and cancellation of traffic restrictions imposed by ATC units which had reached the limit of their traffic handling capacity and the inadequacies of the existing ground-ground communications between adjacent area control centres (ACCs) in the critical areas of the Region resulted in rather unsatisfactory conditions to the operators accompanied by significant financial penalties.

In the field of civil-military co-ordination, the problems created by the simultaneous presence of civil and military operations in the upper airspace still persisted and the required co-operation between civil and military ground services was only slowly gaining ground. In fact, in many instances progress was directly proportional to the establishment of mutual confidence between these two users of the airspace.

In addition, due to the technical advances made in the field of radar on both sides in Europe, the military adopted new flying techniques, the so-called low-level operations, i.e. high speed flights at or below 500m (1600 feet) above the ground. This created an entirely new range of problems between civil "general aviation" flights, i.e. visual flights by light aircraft including gliders and helicopters, and the fast military operations. It was therefore believed that it would be essential to find common ways and means to obtain a form of "co-habitat 1 on" which ensured the essential degree of safety for both parties involved.

Much of the preparatory work to develop arrangements for the resolution of the problems mentioned above was done in Eurocontrol and with active participation by the Paris Office. In order to make these arrangements applicable in the EUR Region, the available material had to be processed through the Paris Office in order to ensure participation and consultation of all interested States in the EUR Region (i.e. Provider States located in the region, as well as user States having an interest in it).

NAT Region

Because of the stalemate regarding lateral separation in the NAT Region, work on the improvement of the air navigation system in the North Atlantic Region and its traffic handling capacity was given very high priority by the NAT Systems Planning Group (NAT SPG) in order to obtain a consensus on the conditions under which a reduction of the lateral separation could be accepted by all parties concerned.

To this extent, the NAT SPG, with the assistance from NAT provider States organised one of the largest traffic data collections which had ever been undertaken in order to obtain detailed information on the actual navigational performance of aircraft while operating in the North Atlantic. This meant not only the recording, by radar, of aircraft positions on either side of the Atlantic and their comparison with ATC flight data but the USA also stationed, for a considerable time, radar-equipped ships in mid-Atlantic under the major air routes to gain navigation information on aircraft at positions which were normally outside any surveillance possibility. To collate and evaluate the information so obtained, extensive use was made of computers which were initially made available by Canada and the United Kingdom and which are now also

In the meantime, the NAT SPG started to develop a mathematical-statistical model to which the data obtained in the collection exercise could be applied in order to determine which separation minimum could be considered to be safe when related to a specific average navigation performance, in other words, which average navigation performance was required to permit the safe application of a specific separation minimum.

As this was an entirely new field in air navigation, it was inevitable that the development of the appropriate methodology and its use in practical application gave rise to considerable discussions before a consensus could be achieved between all parties concerned within the NAT SPG. In any case, by around 1970, it had been found that the best Method to increase the traffic handling capacity in the North Atlantic was to apply a form of composite separation, i.e. to form a basic track system in which parallel tracks were separated laterally by 120 NM and vertically by 600m (2000 feet) and to insert into this system further parallel tracks which were separated by 60NM from any two of the basic tracks but also by 300m (1000feet) from the levels used on these basic tracks :

After a trial period of this new procedure, the Fifth NAT Regional Meeting in 1970 accepted it for routine application and requested the NAT SPG to continue its work towards further reduction in separation in the North Atlantic commensurate with the necessary improvements of the average navigation performance achieved in routine flights by operators. Steps indicated in this direction were:

1. a general reduction of lateral separation to 60 NM, and 

2. a progressive reduction of longitudinal separation.

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