History: Activities of the European Office from 1958 to 1965

EUR Region
Because of the numerous new problems facing the EUR Region as described above, the Fourth Regional Air Navigation (RAN) Meeting for the European Mediterranean Region was held in early 1958 in the UN premises of the former Ligue of Nations in Geneva. This location had been chosen because, by 1958, EUR Regional meetings had assumed proportions in attendance (some 450 delegates) which were only slightly smaller than the General Assemblies of ICAO. This posed many organizational and procedural problems and the services of the secretariat serving these meetings were strained to their limits. The production of working papers, draft reports and, at the end of the meeting a 300 and some pages Final Report, all in two working languages, required not only a perfect Organization but also the burning of a lot of "midnight oil". The conditions have, alas, almost become standard feature of meetings organised by the European Office.
The major problems which faced the 1958 meeting were those created by the expected massive appearance of civil jet aircraft in commercial air transport and the continuous increase of air-tourism during the summer period of each year (end of May to end of September) and the gradual extension of this type of traffic to States located in the Eastern part of the EUR Region.
Pan American inaugurated Boeing 707-121
services in October 1958
Because of the sensitivity of jet-aircraft to operating limitations (uneconomic flight levels. speed limitations, deviations in the route of flight, climb and descent limitations) it was generally felt that the best solution would he to create a two-layer ATS route network:
1. the existing ATS route network in the lower airspace (up to around 6000 m = 20000 feet); and
2. a new, upper ATS route network which should be established above 6000 m (20000 feet) and extending up to some 12000 m = 40000 feet. Contrary to the lower ATS routes, which were already well established and on which in the majority of cases compromise solutions about their routing had been reached between the civil and military authorities, it was expected that the upper air routes, while generally following the alignment of the lower routes, could be arranged so that many of the "dog-legs" (i.e. detours), required in the lower airspace to circumvent military reserved airspace, could he avoided. This would then make for a smoother, more rapid and more economical flow of air traffic.
However, in order to reap the full benefits of this improved upper ATS route network, it was believed that this required also a more effective organisation of the air traffic control services serving this upper airspace. One of the main aspects in this respect was the sub-division of the European airspace into areas of responsibility of specific ATC units (flights information regions (FIR) and associated control areas (CTA)) and, within these, specific controllers. The size of such sectors was normally determined by the maximum number of aircraft which were likely to be simultaneously present in the sector and which could still be handled safely by one man. Passing through different sectors involved for pilots also a change of frequency in the available VHF channels because each controller required an interference-free direct means of communication with the aircraft under his control. 
With the increased speeds of jet-aircraft, it became apparent that, in many cases, the time spent within one sector, or even within a whole CTA, as established for the lower airspace, would not permit the controller, or even an ACC, to do more but noting the entry and, a few minutes later, the leaving of the area by the aircraft concerned. This is turn resulted in an appreciable workload-for the pilot because of the numerous calls and frequency changes which he had to make if this situation persisted on an appreciable portion of his flight. In fact, it was found that, if the lower airspace organisation was retained for jet aircraft, pilots on a 250 nautical mile flight could, in certain cases, be required to make up to 30 calls and change frequencies up to 15 times.
It was for this reason that the idea was born to create a special upper airspace structure consisting of a number of large upper FIRs and associated CTAs which would be served by a reduced number of upper area control centres (UCA), whereby the boundaries of these upper FIRs (UIR) should not be determined by political boundaries but rather by operational and technical considerations. To overcome the inevitable political and juridical problems, it was believed that this could best be achieved by the creation of an international executive organisation to which all those States wishing to participate in this venture would be parties. A project along these lines, started in 1959, culminated in 1963 in the creation of Eurocontrol. Needless to say that throughout its development, the Paris Office of ICAO was participating in this work and rendering any assistance it could.
Already during World War II responsive radar aboard aircraft had been developed which permitted personnel on the ground to differentiate between own and hostile aircraft. Improvement work on this equipment had continued in the civil and military fields and had resulted in world-wide ICAO standards of such a system for civil use under the name of "Secondary Surveillance Radar" (SSR). It envisaged that an aircraft could be assigned a specific code that would appear on the radar screen beside the target representing the aircraft in question, thus facilitating its identification. In a more refined version it was also possible to obtain information on the altitude of the aircraft concerned and, when used in conjunction with automatic data processing equipment on the ground, the aircraft code could even be replaced by its flight number or call-sign, thus avoiding the tedious mental conversion process by the controller from a code to the name of the flight.
However, since SSR was a co-operative system (i.e. one which not only required facilities on the ground but also corresponding equipment on-board each aircraft participating in the system) it was necessary to co-ordinate its implementation not only between States but also with the operators of airlines likely to be affected by its use, especially when this was intended to be made mandatory in specific areas.
Again a limited RAN Meeting was held in Paris in 1962 on this specific subject and it was possible to develop the required technical and procedural measures for the use of SSR in the EUR Region, together with a staged implementation plan.
As to the use of automatic data processing by ATC, work on this subject had been going on in ICAO since 1958. Progress in sophistication and miniaturisation of electronic data processing equipment and a related reduction in cost had made it possible to the industry to produce equipment which was also of interest to ATC where appreciable amounts of data on flights had to be accepted (in the form of flight plans, position reports etc), recorded and processed in order to exercise the required control functions. The increase in traffic and the increase in speed of jet aircraft, with consequent faster control action, appeared to make "automation" a "must" to ATC. However, to use it on an international scale, with the need for equipment of adjacent ATC units to correspond with each other, raised immediately not only the problem of which equipment to use but also that of compatibility between equipment of different manufacturers. The latter aspect was particularly relevant because the costs of such equipment were (and are) still such that any manufacturer was greatly interested to obtain the order for such a system from his home administration. Therefore, the decision to procure such a system could not only be based on purely technical and operational considerations but had an eminent political touch to it.
Therefore, while work on compatibility regarding formats and message conventions proceeded on a world-wide scale in ICAO, the Paris Office was more involved with the development of a realistic implementation programme of ATC automation in Europe which could only be realised step-by-step over an extended period of time and which also had to take account of the side-by-side existence of "automated" and "non-automated" ATC facilities for many years to come. In this respect, it was particularly important that "non-automated" ATC units were not faced with an inordinate high workload, or specific supplementary procedures, simply because they were required to co-operate with an ATC unit which used already automatic processes.
The increasing presence of civil aircraft at and above 6000m or 20000 feet had also raised some problems in the field of altimetry. One of these was the inevitable mixture with military flights and the other the question of vertical separation. It was realised that the continued use of QNH as the altitude reference was unsatisfactory because of the frequent changes of the altimeter setting onboard aircraft and transition problems at the boundaries of designated QNH areas between aircraft operating at adjacent levels but in opposite directions. The other was related to the fact that the decrease in atmospheric pressure, especially at higher levels, does not occur in linear form but along a curve, i.e. the difference in pressure corresponding to given interval in altitude is much smaller at high levels and the inaccuracies, inherent in the systems used to measure altitude in aircraft are therefore more significant and could reduce dangerously the vertical distance between aircraft flying at adjacent levels.
ICAO had therefore developed a new system of altimetry for use during the en-route portion of flights which was based on the use of a standard setting of 1013.2 hectopascals which, when used by all aircraft, served as a world-wide standard reference datum and required no re-setting of the altimeter, except for take-off and landing. The altitude indication thus obtained in the aircraft was called "flight-level" (FL) and it ensured that, regardless of changes in atmospheric conditions, two aircraft operating at adjacent flight levels always maintained the same vertical distance between them. This system also had the advantage that, where altitude information was automatically transmitted to the ground via secondary surveillance radar (SSR, Mode C) no conversion of such data on the ground was required.. To compensate for the atmospheric "inadequacies" described above, it was also agreed that the standard vertical separation between controlled aircraft operating at adjacent flight levels should be increased from 300m (1000 feet) to 600m (2000 feet) for flights above 8850m (29000 feet). If confusion was to be avoided, the introduction of these two measures could only be done on at least a regional basis and this for both, civil and military operators in the whole of the European-Mediterranean Region extending from the USSR to the edge of the North Atlantic and from Norway to the North African coast. Thus the Paris Office became the focal point of co-ordination of this important change to the air navigation system.
NAT Region

Traffic in the North Atlantic Region not only increased continuously but the introduction, by the early Sixties, of four engines jet-aircraft into NAT operations created also new problems, both-in the air and on the ground. In the air, the use of jet-aircraft not only brought a linear increase in traffic but, because of the reduction of the flying time by half and the existing time difference between Europe and North America, a crowding of traffic in both directions into that comparatively small band of hours which permitted the scheduling of flights so that reasonable departure and arrival times could be maintained for passengers.

The first consequence was that, in 1959, a meeting was held in Paris to review the fixed service situation in the North Atlantic and to agree on those improvements which were required to allow for a rapid flow of information (including new meteorological data on the higher levers of the atmosphere) between all parties concerned. In 1961 the Fourth Regional Air Navigation Meeting for the NAT Region was held in Paris and the entire NAT Regional Plan was reviewed and updated so that it was capable of meeting expected demands within the foreseeable future.

By 1965, it was however found that traffic developments in the North Atlantic had gained such a momentum that a further special meeting would be required, dealing with communications and air traffic services. In this meeting, States agreed that, with existing and expected problems in this vital area, it would be necessary to adopt a systems planning approach to the Region as a whole and that such planning should be a continuing process. To this end, the major provider States formed the permanent North Atlantic Systems Planning Group (NAT/SPG) and the Paris Office was charged with providing all necessary assistance to this Group to permit its proper functioning. This Group has met at about yearly intervals ever since and has become the central planning body for the NAT Region.

As to the operational situation, air traffic across the North Atlantic continued to increase at a considerable growth rate and the number of operators flying this route also increased as more large-size jet aircraft were brought into operation. The result was that, during the preferred times, congestion problems arose which meant that a number of flights either were delayed on departure if they insisted on a slot within the comparatively small favourable flight track or they had to accept flight paths which, vertically or horizontally or both, were situated far away from the calculated "minimum time track", with the inherent economic consequences.

It was therefore felt that, to improve the situation, two measures were required, one organizational, the other technical:
3. to obtain reliable information on the expected development of air traffic within this important air traffic area, so as to be able to prepare operationally meaningful traffic forecast over at least the next 5 years; and
4. to develop measures, primarily in the fields of air traffic services and communications which, when applied, would improve the traffic handling capacity of the air navigation system so that it was capable of coping with the demands imposed on it. As regards traffic forecasting, it was agreed that Canada, the United Kingdom and the USA were to form a group which should prepare a North Atlantic Traffic Forecast at yearly intervals, based on economic as well as operational data and related to the major traffic generating areas on both sides of the Atlantic and resultant likely routes to be flown. Necessary secretarial and administrative assistance to this group was to be provided by the Paris Office, which was also charged with the publication and distribution of the yearly forecast to all parties concerned.

With respect to practical improvements it was expected that any organizational or technical changes would require comparatively long lead times because most of these required joint action by the six States (Canada, Iceland, Ireland, Portugal, the United Kingdom and the USA) sharing responsibility for the provision of air navigation services in the North Atlantic. It was therefore believed that changes in the procedural arrangements regarding air traffic control offered the most effective immediate means in order to increase the traffic handling capacity in the Region.

To understand this it should be realised that, because of the meteorological conditions existing over the North Atlantic, there is generally only a comparatively small "corridor"' of limited vertical and lateral extent available in which favourable conditions exist to effect an economic crossing of the Atlantic. In addition, due to prevailing wind conditions, the corridor for a flight from Europe to North America is generally situated much further North than that for flights in the opposite direction. Furthermore, the peak periods of use of these two corridors occurs at different times due to the time difference between Europe and the East Coast of North America, which operators have to take into account to avoid that passengers arrive at some ungodly hour at their respective destinations. In short, there are two peaks of traffic and all aircraft try to get the most favourable track in the available corridors.

The capability to accept traffic in these corridors by ATC is, however, limited by the "separation" standards which has to be applied in order to ensure that, even under most unfavourable conditions, no collision can possibly occur between any two aircraft while flying across the Atlantic. This in turn is dictated by a number of factors over which ATC has very little influence:
5. the reliability and compatibility of weather forecasts upon which individual pilots place their flight planning;
6. the navigational accuracy which can be achieved by aircraft while operating in an area where ground-based navigational guidance by stationary navigation aids on the ground is not possible;
7. the resultant accuracy with which pilots are able to report their position and make estimates on the further progress of their flight; and
8. the speed and ease with which pilot's reports can be received by ATC and resultant control instructions can be passed to pilots for execution.

Based on qualified experience, the separation, practised in the North Atlantic was roughly:
9. vertically 300 m (1000 feet) up to flight level 290 and above that level 600 m (2000 feet);
10. longitudinally (i.e. aircraft behind each other on the same track and at the same level) 30 minutes and, in some special cases 20 minutes (if the preceding aircraft was appreciably faster than the following one); and
11. laterally 120 nautical miles (NM) (i.e. aircraft flying "side-by-side" on parallel tracks and on the same level). For reasons already previously explained, there was little hope that, in the immediate future, anything could be changed in the field of vertical separation. However developments in the navigation field, and more especially the introduction of inertial navigation systems onboard aircraft, made it appear likely that reductions in longitudinal and lateral separation could be envisaged with appropriate safeguards and that these would, obviously, have immediate beneficial effects on the traffic handling capacity of the ATC system.

It was for this reason, and based on studies which had been conducted in the USA, that the Special NAT Meeting agreed on a reduction in lateral separation from 120NM to 90NM as a first step to alleviate traffic congestion in the North Atlantic. This decision met however with strong objections on the part of pilots. It was therefore agreed to suspend the application of this new lateral standard until all parties concerned were convinced that it could be applied safely. To obtain such an agreement, it was expected that the NAT SPG would propose appropriate measures. In the meantime, the status qu4) was maintained in the NAT Region with all its consequent economic penalties for the operators.

Because of the numerous new problems facing the EUR Region as described above, the Fourth Regional Air Navigation (RAN) Meeting for the European Mediterranean Region was held in early 1958 in the UN premises of the former Ligue of Nations in Geneva. This location had been chosen because, by 1958, EUR Regional meetings had assumed proportions in attendance (some 450 delegates) which were only slightly smaller than the General Assemblies of ICAO. This posed many organizational and procedural problems and the services of the secretariat serving these meetings were strained to their limits. The production of working papers, draft reports and, at the end of the meeting a 300 and some pages Final Report, all in two working languages, required not only a perfect Organization but also the burning of a lot of "midnight oil". The conditions have, alas, almost become standard feature of meetings organised by the European Office.

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