Despite the limited
Regional Meeting in 1968 and 1969, it was found that developments in the
EUR Region required a further full-scale Regional Meeting in 1971 in
order to up-date the air navigation system and make necessary provisions
for the next couple of years. As already found in 1958 at the Fourth
and in 1966 at the Fifth Regional Meetings, the size and complexity of
the Meeting was again such that it proved impossible to prepare a
complete Regional Plan in the time allotted to the meeting. In addition,
it was also found that future developments in the Region were charged
with by so many imponderables that reliable forecast about them and
consequent measures based thereon could not be developed.
The Meeting agreed therefore on a new method of regional planning that envisaged:
a.
a continuous review of the Regional Plan in order to adjust it in the light of developments, and
b.
the creation of a special body, composed of
representatives from designated States of the Region, in order to
conduct this review and prepare, as necessary, proposals for corrective
action which could be presented for adoption to all States of the Region
(providers and users) whenever this was required by circumstances. As
this appeared to many to be a rather drastic departure from the regional
planning machinery, so far applied by ICAO on a world-wide basis, it
was, however, agreed that this new process should be conducted on a
trial basis and that a definite decision on it should only be taken once
sufficient experience had been gained to allow a final judgement.
The Group constituted in accordance with the above was called the European Air Navigation Planning Group (EANPG) and, after its constitution agreed on the following working method:
c.
the full group would meet twice yearly in plenary session
to review the situation and based on this, propose action required to
keep the Regional Plan current and/or to initiate action required to
make timely arrangements for likely future requirements; and
d.
the group would create working groups of limited duration,
which were given specific tasks and which were to report the results of
their work directly to the EANPG. The result of this was that, at
times, up to 6 different working groups of the EANPG were in operation
and, since the Paris Off-ice was charged with the task to give all
necessary support to the EANPG and its subordinate bodies, its workload
was considerably increased. In fact, this went so far that, in some
years, some 30 to 35 meetings on a wide variety of technical and
operational subjects had to be organised and serviced in the Paris
Office and this in addition to the routine office tasks. However, at the
same time, this activity also resulted in much closer international
co-operation, especially in the fields of air traffic services,
communications, aeronautical information services, communications,
aeronautical information services, meteorology etc. than had previously
been the case and this continuous collaboration between States
strengthened the recognition amongst States that the air navigation
system in the Region was truly international in nature.
The increase in sophistication and complexity of the
equipment used in air navigation in general and especially in the
provision of air traffic control accentuated two problems which had
already previously existed but which now assumed major proportions:
e. the state of development of the national air traffic
services in the Region varied considerably. This applied not only to the
availability of supporting means (primary and secondary radar,
communications, data processing equipment etc.) but also to the
administrative and social provisions applicable to ATS personnel; and
f. once a certain complexity of the system had been
reached, its further improvement became more and more costly, while the
additional benefits obtained from these improvements (i.e. increases in
traffic handling) tended to become smaller and smaller. In fact, it was
found that, in certain highly developed national facilities, an expected
increase in the traffic handling capacity by 10 % would increase the
operating costs by some 50 to 70 %. The problem under a) required that,
in any planning, account had to be taken of the existing situation and
of the realistic possibilities of States regarding improvements to their
ATC system, and this not only from the financial point of view but also
with regard to "lead-times" of the industry manufacturing the required
equipment and the necessary "break-in" time by personnel using the
equipment routinely before it could be used to full advantage. In
addition, it had also to be ensured that differences in sophistication
between ATC facilities in adjacent States did not result in the
imposition of unduly complicated or cumbersome operating methods on the
less sophisticated unit, thus adding to its workload and operating costs
without any gain in efficiency.
With respect to b), it was inevitable that the review
of this question raised, on the one hand, the question of the ultimate
traffic handling capacity which an air traffic control system could be
expected to attain and, on the other, the costs which were involved in
such a process. In short, the question of a reasonable relationship
between cost and effectiveness of the air navigation system, which had
already previously been a planning factor, albeit not of major
significance, now assumed proportions which influenced more and more the
technical and operational planning.
The question of the ultimate capacity of the air
navigation system was, however, not only seen under cost aspects but it
was also realised that technical developments had reached a stage where
it was no longer possible to work with the philosophy so far applied
that, if demand increased, human ingenuity would always find ways and
means to satisfy it. A major event provoking discussion on this subject
was the so-called "oil crisis" in 1973, which had far-reaching
consequences on air transport in general and thus on air navigation. To
mention just one aspect: fuel costs which had hitherto constituted some
10-12% of the total operating costs of an airline operator now rose to
some 30-35 % of them. The immediate effect of this was that operators
placed even more emphasis on the economy of their flight operations,
i.e. they became much more sensitive to delays and/or route or altitude
penalties imposed on their flights because the resultant additional fuel
costs for a flight had a much greater impact on its economic
efficiency.
However, since the oil crisis had also marked effects
on the general economic situation of practically all States, this, in
turn, meant that they began to review their budgets for possible new
sources of cost recovery with the result that amongst others, the free
use of the en-route part of the air navigation system received closer
attention, not the least because of the growing costs involved in its it
was therefore believed necessary to explore other avenues. It was noted
that the difficulties in the handling of air traffic were not equally
distributed throughout a day, or throughout the week or the year. They
occurred only during specific periods of the year (summer holiday
season, Christmas season, Easter, specific events) and mostly during the
end of the week and therein again at specific hours of the day, In
addition, this peaking of traffic only affected certain heavily
travelled routes and areas where large amounts of traffic were generated
and this, in turn, was largely dependant on passenger habits or in some
cases what operators thought passenger habits were. However, the
effects of such a partial clogging up of parts of the route network
extended nevertheless far beyond the immediately affected area.
Uncoordinated efforts made by individual ATC units to limit the
acceptance of air traffic in their area to a degree commensurate with
their handling capability proved not only ineffective but increased the
overall difficulties in size as well as in the affected area
modernisation and in the resultant operating expenses. In short, by the
mid-seventies, user charges for en-route services in order to recuperate
progressively more and more of the operating expenses spent by States
were a common theme in the Region. This gave an additional impetus to
the cost-effectiveness discussions mentioned above and established
economic considerations definitely as a major subject in any further
planning for the air navigation system.
On the technical side and for the reasons stated above,
it was realised that the limitations to the traffic handling capacity
of the system, which continued to persist, could not be resolved at
short notice by a simple expansion of the system capacity. In fact,
there was doubt that this could ever be done in the light of the new
economic situation and
Therefore, it soon became apparent that, if any
scheduling measures intended to spread air traffic in time were to be
taken, this could only be done on the largest possible scale, preferably
on a regional basis. In addition it had to be ensured that any
limitations imposed on operators could only be taken while their
aircraft were still on the ground and it had to be ensured that such
limitations affected all operators in an equitable manner. After long
and complicated discussions, two possible alleviating measures were
developed which, while not eliminating the difficulties, at least
provided a certain alleviation of the unsatisfactory situation:
g.
the progressive implementation of a one-way routing system
between those points in Europe where most of the traffic was generated.
This reduced not only the number of intersecting flights but allowed a
tighter packing of air traffic along particularly heavily travelled
routes; and
h. the progressive creations of a data bank on all repetitive flight
operations so that ATC units could anticipate likely traffic loads and
make appropriate manning and other arrangements.
In addition, certain procedural arrangements regarding
the filing of flight plans and the transfer of flights from one ATC unit
to the next were made which helped to accelerate and facilitate the
flow of flight data and thus the flow of air traffic. Needless to say
that Eurocontrol made valuable contributions in this respect and that
the EANPG was a major asset by assuring the earliest possible
application of any agreed relief measure, as well as by encouraging the
specialised groups, dealing with these matter's, to reach speedy results
of their work. That all these activities required continuous assistance
by the Paris Office goes also without saying whereby not the least task
was to keep all States interested in the EUR Region currently informed
of all developments in order to avoid any feelings amongst States, not
directly participating in this work, that their legitimate interests
were not properly taken into account.
At the same time, the EANPG made a complete review of the
modalities which had so far been used to develop and maintain current
the Regional Plan for the EUR Region in order to make it a more
effective tool not only for international but also for national planning
by States. To this extent, it was necessary to redefine a number of
basic concepts of regional planning and the relationship between the
demands on the air navigation system as formulated by the users and
their realisation by States after a consensus on them had been reached.
In addition, it was agreed to include, into the Regional Plan, certain
methods used by States which, when applied on a wider scale, would
ensure more uniformity in the operation of the air navigation system. As
a result of this work, the Regional Plan now contain:
i.
assumed operating parameters, i.e. selected performance
characteristics of aircraft, which can be assumed by ground services in
rendering services to them;
j.
basic operational requirement i.e. agreed needs which the
air navigation system has to meet if it is to function satisfactorily;
k.
planning criteria, i.e. all aspects which need to be taken
into account when planning an efficient, economic and practical air
navigation system; and
l.
methods of application, i.e. efficient and economic ways to
operate the air navigation system and which, when applied on a wider
scale, make for more uniformity in the way in which the air navigation
system is operated. It was also agreed to include, in the Regional Plan,
material on specific subjects which were not yet of general concern
throughout the Region but which could serve as guidance to States in
their planning, once they were confronted with the need for action on
the subject in question.
The above, seemingly somewhat abstract
activities of the EANPG showed their essential importance as the EAN PG
got more involved in the planning of complex sub-systems of the air
navigation systems which were required to cope with additional or new
requirements. Apart from the new subject of "air traffic flow
management", the increased requirement for up-to-date aeronautical
information on the operating status of the system and its facilities,
latest meteorological information and Other relevant data, increased the
amount of data which needed to be exchanged as well as the speed with
which it had to be made available. It was evident that, in the long run,
it would economically not be possible to provide special dedicated
communication networks for each of these types of information. It was
for this reason that world-wide efforts within ICAO to provide for one
integrated exchange system for all data gained particular importance in
the EUR Region and work on the "Common ICAO data Interchange Network
(CIDIN)" received priority treatment by the EAN PG, even though it was
realised that its practical implementation throughout the Region would
require a comparatively long period.
At the same time it became apparent that the creation of
such complex systems raised a number of new problems, not the least of
which was the need for more rigidity in sequence and format in which
data was inserted into the systems and the increased use of codes and/or
abbreviations by the system to save space and time. In short, the
intellectual and physical task of preparing data so that it was
acceptable to a given technical system for manipulation, and the correct
interpretation of results produced by the system, required more and
more specialised skills from the operator concerned, thus detracting him
from his major duty, i.e. to serve air traffic. It was therefore
believed necessary to strike a reasonable balance between automation
(with its inherent rigidity) and the need for flexibility in the
application of procedures by human operators to cater for non-routine
situations. Finally, it was found that, the more expanded such systems
were, the more difficult it became to Make changes to its operation in
order to respond to new or changed requirements and this for mere
technical reasons such as changes in the software and the associated
inevitable debugging and/or modifications of specific data manipulation
processes by the equipment.
As of the mid-seventies, it was also found that, due to
the increase in general aviation activities (i.e. non-commercial flight
operations in the lower airspace and around already busy airports and
their mixture with low-level military flight operations, especially in
the crowded Central European airspace) a new requirement for improved
air traffic services to this type of flights arose. To make this
possible, some States developed a new airspace structure with associated
advisory services and/ or mandatory requirements for the carriage of
specific types of navigation and/or communication equipment and the
certified ability of pilots to use these. However, as these new problems
'were originally only felt by a limited number of States, each of them
sought its own solution to it, with the end result that, by 1978, a wide
variety of requirements and operating practices were in use which,
while adequate for the local area in hich they were applied, rendered
life fairly confusing for pilots engaged in international operations
because of the need for frequent adjustment to new environments and
procedures.
The EANPG therefore agreed on the need for work in this
field in order to develop a common policy amongst all States concerned
and also a common set of provisions. Very soon it became apparent
however that a basic solution to this question could not be limited to
the EUR Region alone but might require a revision of existing world-wide
ICAO provisions regarding the visual flight rules and the
classification of airspace. Based on the conditions existing in the EUR
Region, the EANPG prepared a number of proposals and these are now under
consideration by ICAO in a worldwide review.
By 1980, the work of the EANPG had progressed to a point
where it was felt necessary to present it to a special Regional Meeting
in order to find out whether States were in agreement with the manner in
which the EANPG operated and also to obtain a mandate and, if
necessary, new directives for its further activities. In addition, the
specific subject of air traffic flow management, one of the main
preoccupations in the Region, had been developed to the point where it
was advisable to obtain a region-wide policy-decision as it was evident
that any measures in this field would have at least region-wide
implications. This applied particularly to the regional data bank on air
traffic movements for whose creation Eurocontrol had become the focal
point. Based on proposals presented to the Meeting, it agreed that the
activities of the EANPG should continue and that work on air traffic
flow management, including the establishment of a central air traffic
data bank, should be pursued along the lines proposed.
After 5 more years, during which the EANPG continued its
work while constantly refining its working methods in the light of
experience gained, the Seventh Regional Air Navigation Meeting was held
in 1985 in Malaga (Spain) and it produced the following results:
m.
it defined permanently the basis on which air navigation planning in the Region should be conducted;
n.
it agreed on the structure and presentation of the E U R Regional Plan;
o.
it agreed on the manner in which the Regional Plan should be
managed, including the retention of the EANPG as the permanent managing
organ;
p.
it defined the scope and structure of future EUR Regional Meetings;
q.
it developed the measures required to improve the airspace
organisation and the flow of air traffic in the Region; and
r.
it described likely future developments and trends in air
navigation in the medium and long term. Translated into practice this
means that regional planning in the EUR Region is now done on a
permanent basis with the possibility of inserting into the planning
process latest developments on the international as well as the national
level of individual States. To this extent, the Paris regional office
will serve as the focal point at which all information will be collected
and where arrangements will have to be made for its processing and the
inclusion of relevant decisions and agreements into the EUR Regional
Plan.
Quite apart from achieving very substantial practical
results, it should also be noted that this Meeting was able to conclude
its work in only 11 days, as compared to the previous 4 weeks of hectic
activities. This also was mainly due to the fact that, because of the
preparatory work done under the auspices of the EANPG, the Meeting had
been presented with a comprehensive supporting documentation and clear
and concise proposals.
Concorde, the first supersonic aircraft used
to cross the Atlantic, reduced the flight time by half
NAT Region
The
introduction of "composite separation" in the North Atlantic track
system had brought a certain relief to the traffic congestion in that
Region because it increased the traffic handling capacity during peak
periods. However, it soon became apparent that this could only be
considered as a temporary relief measure. This even more so because the
main difficulty still remained, i.e. the comparatively large economic
penalties for all those flights which could not be accommodated on those
tracks which were aligned in the narrow corridor surrounding the
"minimum time track" (it is recalled that the normal lateral separation
between adjacent tracks on the same level was still 120 nautical miles.
To make things worse, the "oil crisis" of 1973 and its consequences on
the operating costs significantly increased the economic penalties for
those flight operations which were required to operate along the outer
edges of the NAT track structure and more especially those which,
because of their origin and destination (Southern Europe to Canada and
vice versa), were required to cross the main East-West traffic flow.
These flights could only fly under the track structure or above it, the
latter not always being possible because of aircraft weight limitations,
and this meant flight at uneconomic levels over long distances as long
as the lateral extent of the route structure was a multiple of 120
nautical miles.
It was for this reason that, from 1971 on, the NAT SPG
concentrated its efforts on the possibility of reducing the lateral
separation between adjacent tracks in the track structure to 60 nautical
miles, thus reducing its overall lateral extent by about half and
bringing appreciable economic relief to both, crossing flights as well
as those required to operate at the outer tracks of the structure
itself. (An intermediate reduction to 90N M as agreed in 1965 was, for a
number of practical reasons not found suitable). It was, however,
realised that such a "quantum jump" in the reduction of lateral
separation could not be achieved without appropriate safeguards in order
to maintain the essential safety of flights. Of these, the most obvious
was to ensure that the pilots' ability to follow their assigned route
as closely as possible was ensured under all likely circumstances. The
most promising development in this respect was the continuous increase
in the number of aircraft equipped with inertial navigation systems and
the availability of the long-range navigation system "OMEGA". Experience
with these two systems had shown that, on average operations across the
North Atlantic, aircraft could keep to their assigned track within very
close tolerances and also that the reliability of these systems was
sufficiently high to make failures a comparatively rare event.
Based on these conditions, the NAT SPG
developed a concept which envisaged that States would ensure that
aircraft on their register - would meet specified values of navigational
accuracy (minimum navigation performance specifications - MNPS) and
that only aircraft so certified could operate within a specified area in
the North Atlantic where a lateral separation of 60NM between adjacent
tracks would be applied. At the same time, the NAT SPG developed a
proposal for the reduction of longitudinal separation between successive
jet-aircraft on the same track and the same level, based on experience
gained by oceanic control centres on both sides of the Atlantic. This
so-called Mach Number technique envisaged that aircraft following each
other would be assigned to this speed with the least possible variation.
This then made it possible to assume that, while the assigned distance
between any two aircraft (expressed in time of passing over the same
reporting point) could slightly vary due to the fact that the two
aircraft could, at any given time, be exposed to different
meteorological conditions (especially winds), they nevertheless could
never come in dangerously close proximity to each other.
In 1976 these proposals of the NAT SPG were presented to a limited Regional Meeting of North Atlantic States
and were there adopted for application in the NAT Region. In 1977, the
MNOS area was established in the NAT Region and, while still retaining
120NM normal lateral separation with the addition of a few tracks, based
on composite separation, only MNPS certified aircraft were allowed to
operate in the designated MNPS airspace. This was done in order to
obtain data on radar-observed track deviations, which could serve as a
basis for the assumption that the use of 6ONM lateral separation was
feasible. Three years of observation and indoctrination of all concerned
by States and operators through constant education and follow-up of
recorded deviations with crews concerned resulted by 1980 in a situation
where all parties concerned (States, operators and pilots) reached a
consensus that the use of 60NM lateral separation in the designated MNPS
airspace was a sage procedure.
At the same time, the consequent application of the Mach
number technique had also shown that a reduction of the longitudinal
separation from 30 to 15 minutes was also a sage proposition. It Was
therefore agreed that these new separation minima, together with a rigid
surveillance system and a specific follow-up procedure for each case of
an observed abnormal deviation from track, should be implemented as of
autumn 1980 and the results achieved to this day have shown that these
measures were fully justified by practical experience.
With respect to these measures, it should be noted that
they constituted the result of some 15 years of probably the most
profound studies ever made in air navigation' matters and that they had
been achieved thanks to an international effort by States and
international organizations which despite differences in technical and
procedural matters, had been conducted in a truly co-operative spirit
and for the benefit of international air transport.
Since 1981 and up to 1985, the NAT SPG has continued its efforts to improve the air navigation situation in
the North Atlantic while maintaining the extraordinary safety record in
that Region. This work envisages, inter alia, improvements to the
methods of flight planning by the provision of still better
meteorological data, more flexibility in the conduct of flights and
further reductions in the separation applied between individual flights,
commensurate with improved methods of navigation and surveillance and
without loss of safety.