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									                                      IATA European RTC/6                     Agenda Item 12.1.
                                        Brussels, Belgium                    Working Paper 12.1.
                                       24-26 October 2000                                Page 1

                      EUROCONTROL, BRUSSELS
                          24 – 26 October 2000

Agenda Item 12.1. : Expansion of the 8.33 kHz area

           Expansion of the Application Area of 8.33 kHz Channel Spacing

                                     Executive Summary

The implementation of 8.33 kHz channels spacing in the core area of Europe has provided the
expected short-term frequency release, with the channel needs of the so called 8.33 States being
met with a high success rate.

At the same time simulations and follow-up action conducted by EUROCONTROL show that if
nothing further is done, the aviation part of the VHF band will, by the end of 2002-3, face
similar constraint to those experienced before the original implementation of 8.33 kHz channel

The difficulties already being experienced by those States still using 25 kHz spacing further
highlight the need for urgent action.

This is not unexpected, as it had already been foreseen in the planning stages of the original
implementation that it would provide only temporary relief up to about 2003.

Initiatives are under way to provide VHF spectrum relief. These include improved frequency
management in the whole of Europe and alternative technologies (e.g. VDL Mode 3), but these
are not expected to bring appreciable results before 2005-7.

Expanding the 8.33 kHz application area horizontally via the structured and co-ordinated
retraction of the existing temporary exemptions would provide an effective way of providing
spectrum release in the short term, catering for frequency demand up until the time new
technologies are expected to provide a more permanent solution.

Meeting the demand for frequencies, and thereby preserving the ability of pilots and controller
to communicate via voice, is an operational imperative.

It is therefore proposed to expand the 8.33 kHz channel spacing area horizontally on 31 October
                                   IATA European RTC/6                   Agenda Item 12.1.
                                     Brussels, Belgium                  Working Paper 12.1.
                                    24-26 October 2000                              Page 2

                     EUROCONTROL, BRUSSELS
                          24-26 October 2000

          Expansion of the Application Area of 8.33 kHz Channel Spacing


1.   The ability of pilots and air traffic controllers to communicate via voice is one of
     the oldest, basic elements of the ATM system. Advances in ground and airborne
     automation do mean that in the not too distant future we will be using this facility
     in a different way, with an increasing amount of voice being replaced with data
     communications. However, even in the most advanced ATM environment, voice
     communications will continue to play an indispensable role.
2.   The resource used to enable voice communications, the aviation spectrum, is
     limited and the demands being put on it have already resulted in a scarcity of
     frequencies that can be allocated to the services needing them. In many cases,
     requests for frequencies go unsatisfied, or less essential services (e.g. automated
     weather reporting) are terminated with the corresponding frequency being
     reallocated to the more essential service.

3.   An examination of ongoing and planned ATM enhancements shows conclusively
     that the need for additional frequencies will continue to increase for the
     foreseeable future. The main sources of this requirement are:

     a.   The introduction of Controller-Pilot Data Link Communications (CPDLC)
          will not take away the need for voice channels in sectors using CPDLC;

     b.   Airspace structure developments and the introduction of RVSM will require
          new sectors in some States and these will need new frequencies;

     c.   New control centres. In Europe CEATS will require its own set of frequencies
          and these cannot all be provided by what may be freed from the national

     d.   VHF Digital Link (VDL). In order to eliminate interference between voice and
          data modes, guard bands will need to be implemented around the frequencies
          allocated to VDL. While the exact number of frequencies implicated in this is
          still the subject of further study, a realistic expectation is that 10-15 25 kHz
          channels will have to be released in Europe for this purpose. The eventual
          need for additional VDL frequencies will only increase this number.

     e.   To meet additional demand and/or to re-allocate existing frequencies, a certain
          flexibility is needed in the frequency allocation process. This flexibility can
          only be provided if there is a sufficient number of “free” frequencies, which
          can be moved and shifted around. With the part of the aviation spectrum using
          25 kHz channel spacing nearing saturation in Europe, the required flexibility
                                     IATA European RTC/6                    Agenda Item 12.1.
                                       Brussels, Belgium                   Working Paper 12.1.
                                      24-26 October 2000                               Page 3

          disappears and this makes the frequency management process extremely
          difficult. Additional frequencies are needed to restore flexibility.

4.    Considering that the ability for pilots and controllers to talk to each other via voice
      will continue to exist as a primary element of the ATM system, it is fair to say that
      meeting the demand for VHF frequencies is an operational imperative. Cost
      effective ways must be found to satisfy this imperative, but it would be wrong to
      make this contingent upon extra benefit considerations.

5.    The European answer to the frequency shortage had been the introduction of 8.33
      kHz channel spacing for services above FL245 and with the initial application area
      limited to the core of Europe.

6.    The implementation of 8.33 kHz channel spacing has indeed delivered the
      expected short-term frequency benefit, but this was obviously limited to the States
      which participated in the actual implementation. It should be noted that the less
      then optimum operational introduction of the new frequencies was due to
      circumstances (e.g. lack of controllers to man the new sectors) quite unrelated to
      the new channel spacing.

7.    The benefit of 8.33 kHz channel spacing in satisfying the need for new frequencies
      is amply demonstrated by a comparison of the success rate in 8.33 kHz
      participating States and that in 25 kHz States. According to data made available
      from the European Air Navigation Planning Group’s (EANPG) Frequency
      Management Group (FMG) 8th Block Planning Meeting in December 1999, the
      success rate for 8.33 kHz States was 100 %, while the success rate for 25 kHz
      States only 43 %.

8.    This very low result for the 25 kHz States can be traced to the generally poor
      quality of the frequency management process in Europe and, more significantly, to
      the very large number of shifts needed to actually implement an allocated new
      frequency (in some cases as many as 32 to implement 47 new frequencies). This is
      compounded by the fact that currently there is no mandatory requirement for States
      to actually implement the frequency assignments/shifts as planned by the Block
      Planning Meetings.

9.    Simulations conducted by EUROCONTROL, based on the forecast increase in
      frequency demand, show that, in addition to the current difficulties in meeting the
      demands in States using 25 kHz channel spacing, if nothing is done, by 2002-3, the
      VHF spectrum in Europe will once again face similar constraints to those
      experienced before the initial implementation of 8.33 kHz channel spacing. Note:
      This is not unexpected and had been predicted in 1996 in the “Plan for the 8.33
      kHz Channel Spacing Implementation in Europe – Edition 2.0”.

10.   While a decision to address the shortcomings of the European frequency
      management process (c.f. MATSE6) will undoubtedly result in some
      improvement, this is not expected to release sufficient spectrum in time to alleviate
      the upcoming problem.
                                      IATA European RTC/6                    Agenda Item 12.1.
                                        Brussels, Belgium                   Working Paper 12.1.
                                       24-26 October 2000                               Page 4

Possible Solutions

11.   In searching for a solution to the frequency shortage, the very short period
      remaining until its expected occurrence must be kept in mind. The following
      alternatives have been examined:

      a.   Extension of the VHF spectrum. In view of the fierce competition for
           spectrum by other industries, achieving this is highly improbable. In any case,
           this solution is very costly, considering the retrofit implications. Furthermore,
           any such extension could only be expected to occur at a date well beyond the
           stated requirement.

      b.   Better frequency management. Achieving this in Europe is essential, however,
           as mentioned above, even a much improved frequency management process
           will be unable to release sufficient spectrum and even modest improvements
           will take several years to implement.

      c.   Introduction of VDL. As already mentioned, sectors using CPDLC will
           continue to have a need for a dedicated voice channel.

      d.   Wide-band voice/data. A proposal to use part of the C-band, currently
           allocated to MLS, with Code Division Multiple Access (CDMA) technology,
           is currently being examined. However, a lot of work remains to be done, and
           implementation, if any, cannot be envisaged before 2010. Even then, this
           solution would work only in the TMA/Airport environment.

      e.   Wireless gatelink. While services on wireless gatelink are expected to be
           increasingly available in the near future, this solution is strictly for the airport
           environment. While it will provide some VHF spectrum congestion relief at
           airports, it does not address the problem being faced by services outside that

      f.   VDL Mode 4. Currently being considered for surveillance services only. A
           decision for industry-wide application beyond surveillance is not expected
           within the problem-time frame.

      g.   VDL Mode 3. VDL Mode 3 is an integral part of the US NEXCOM program.
           In its ultimate form it can provide combined digital voice/data service,
           however, initial implementation in the US foresees only digital voice and this
           in the timeframe 2007+. Europe does not, as yet, have a comparable program.
           Even with a swift implementation decision, VDL Mode 3 is well outside the
           problem-time frame.

      h.   Vertical expansion of the 8.33 kHz application volume. Simulations indicate
           that a vertical expansion (below FL245/FL195) of the 8.33 kHz application
           volume would be far less efficient in terms of frequency release than the
           original 8.33 kHz implementation. It would also impact a very large number
           of aircraft and several new categories of airspace users. Considering the costs
           and logistics involved, no implementation before 2007 can even be
           considered. Apart from the fact that this in itself puts this solution firmly
                                     IATA European RTC/6                    Agenda Item 12.1.
                                       Brussels, Belgium                   Working Paper 12.1.
                                      24-26 October 2000                               Page 5

           beyond the problem time frame, the wisdom of extending an analogue system
           into the lower airspace at a time by which digital systems are expected to
           mature is highly questionable. The airspace user community has repeatedly
           voiced the opinion that this was a non-option and should not be further

      i.   Horizontal expansion of the 8.33 kHz application area. The high success rate
           of satisfying frequency needs in the existing 8.33 kHz States makes this option
           very attractive. Such expansion involves only the horizontal extension of
           already existing provisions and procedures, with the additional impact on
           airspace users being sufficiently limited to make implementation by the 3rd
           quarter of 2002 a realistic proposal.

Proposed Solution

12.    From the list of options above, it is clear that only one solution is available to
      meet the challenge of the problem time-frame, namely horizontal expansion of the
      8.33 kHz application area. This option offers the following additional advantages:

      a.   Regulatory background. The carriage and operation of 8.33 kHz capable radio
           equipment is already mandatory in the whole of the ICAO EUR Region, as
           published in Doc. 7030, Regional Supplementary Procedures-EUR. Non-8.33
           equipped aircraft are currently allowed to operate in certain parts of the EUR
           region on the basis of temporary exemptions published by a number of States.
           However, these exemptions have always been identified as “temporary” which
           can be withdrawn after appropriate consultation with the airspace users (8.33
           User Guide para. 7.4 refers). Therefore, extension horizontally involves only a
           structured retraction of some or all exemptions and does not need additional
           ICAO provisions.

      b.   Number of aircraft to be retrofitted. The number of aircraft to be retrofitted
           with 8.33 kHz capability is estimated to be in the order of 900. This number
           was arrived at using the very comprehensive fleet survey that had been
           conducted before the original 8.33 kHz implementation. At that time a
           thorough inventory of all airlines (scheduled and non-scheduled) operating
           anywhere in the EUR region had been prepared. Airlines which did not
           responding to the first approach to supply existing and planned fleet data were
           followed up individually. The number of aircraft to be retrofitted in case of a
           horizontal expansion has now been calculated on the basis of the known fleet
           numbers involved in the first implementation. Since practice has shown that
           this number was very accurate, the number of aircraft still to be fitted can also
           be considered reasonably accurate, even if possible changes within the past 18
           months are taken into account. In any case, a new survey will be conducted to
           confirm the numbers, but it is not expected to result in a substantially different

      c.   Costs. Based on the per-airframe cost of USD 40.000, the costs for 900
           aircraft would come to USD 36.000.000. The costs incurred by ground radio
           replacement/upgrades are more difficult to estimate in view of the many
                                     IATA European RTC/6                   Agenda Item 12.1.
                                       Brussels, Belgium                  Working Paper 12.1.
                                      24-26 October 2000                              Page 6

           different types of equipment and environments. Since it is known that several
           of the candidate 8.33 States are in the process of procuring new ground radios
           in the 2001-2 time frame, as part of their normal renewal activity, and since
           most new radios will be 8.33 capable, the actual ground radio costs
           attributable to 8.33 expansion will be limited.

      d.   Logistics. Although the original 8.33 implementation program has now been
           officially terminated, the modus operandi employed is well rehearsed. The
           instruments used (Project Management Cell, Technical Retrofit Meeting,
           Contact Persons’ Meeting, etc.) can be activated again at any time, with
           participation slightly adjusted to take account of the new 8.33 States. Even this
           can be limited, since most of the current candidate States had been involved in
           the original implementation in their capacity as “buffer” States.
           Documentation (User Guide, AICs, AIP entries, Letters of Agreement) has all
           been developed for the original implementation. Most of these can be re-used
           with minimal changes, resulting in substantial savings of effort. With the
           majority of exemptions likely to be withdrawn, the operational environment
           will become simpler resulting in reduced training effort for airspace users.

      e.   States’ willingness to implement. Most States in the proposed horizontal
           expansion area have already indicated their plans to implement the new
           channel spacing on the proposed date (31st October 2002, see below). The
           implementation date may be later in some States, but they would still
           participate in the expansion exercise to facilitate co-ordination. Other States
           may join the implementation purely on a strategic basis, to ensure the largest
           possible homogenous expansion area.

      f.   Flexibility in the number of States actually joining. The spectrum release
           potential of horizontal expansion is directly related to the number of States
           involved. The larger this number, the greater the benefit. However, there is no
           set minimum number to make the exercise worthwhile. This means that even
           if a number of States decide not to participate, substantial spectrum benefits
           can be realised. In any case, with the number of States already having
           indicated their desire to participate, horizontal expansion will bring enough
           spectrum release to meet the forecast demand up to about 2007.

      g.   Time to implementation. In view of the relatively low number of aircraft to be
           retrofitted, the already existing plans for ground radio upgrades and the
           reusability of the logistics arrangements and the continued applicability of
           existing regulatory provisions, time to implementation can be short, and
           accordingly 31st October 2002 is being proposed. This date fits well with the
           expected occurrence and increasing severity of spectrum congestion in

13.    Based on the experience with initial 8.33 kHz implementation and simulations of
      an expanded area, horizontal expansion of the 8.33 kHz application area would
      result in the following benefits:

      a.   When a frequency, originally operated on 25 kHz spacing, is converted to 8.33
           kHz spacing on the matching centre 8.33 kHz channel, it can immediately and
                                    IATA European RTC/6                   Agenda Item 12.1.
                                      Brussels, Belgium                  Working Paper 12.1.
                                     24-26 October 2000                              Page 7

           without any shifts whatsoever accommodate the two shoulder frequencies
           under the coverage of the original 25 kHz frequency. Consequently, the
           chances for successful implementation are increased drastically, as
           evidenced by the success rate in the current 8.33 kHz area.

      b.   While the spectrum benefits are spread across the whole of the VHF band,
           the majority of the benefits accrue within the current 25 kHz
           environment, exactly where it will be needed most

      c.   The newly created frequencies mean that the frequency management process
           no longer has to operate in a near saturation (and therefore almost paralysed)
           mode, since the necessary flexibility in reallocating existing frequencies as
           required is restored.

      d.   The new frequencies enable the meeting of new frequency demand without
           requiring extensive shifting.

14.   Consequently it is proposed to expand the 8.33 kHz application area
      horizontally via the structured retraction of current exemptions starting on
      31 October 2002. The expanded area would cover as a minimum the States
      adjacent to the current 8.33 area, and may eventually extend beyond those States to
      the outer ECAC boundary. The exact list of States is still to be determined.

IATA Involvement

15.    IATA’s European Operations and Infrastructure Office has played a pivotal role in
      the original 8.33 kHz implementation. Not only did IATA provide a constant line
      of information to and from the airline community, but it also helped in the
      development of procedures and monitoring facilities. The value of this
      contribution has been amply recognised by the airlines, air traffic service providers
      and EUROCONTROL.

16.   While the effort involved in the horizontal expansion of the 8.33 kHz application
      area is smaller than that for the original implementation, IATA’s involvement on a
      similar level will be essential if the same, smooth implementation is to be assured.

17.   It is estimated that the effort involved will be between 5-10 % of the time of one
      person until the end of 2001 and about 5 % thereafter until the implementation
      date. Therefore no additional resource will be required.

Program risks

18.    The need to release spectrum as soon as possible has resulted in an
      implementation date that is only 2 years from program go-ahead. Meeting this
      deadline will require careful planning and tight control of the program, as well as
      full co-operation of airlines, equipment manufacturers and ATS providers.
                                    IATA European RTC/6                  Agenda Item 12.1.
                                      Brussels, Belgium                 Working Paper 12.1.
                                     24-26 October 2000                             Page 8

19.   Some of the aircraft types which will have to be retrofitted may not have been
      involved in the original implementation and this may need individual attention.
      However, the methods employed with success in the first implementation should
      be sufficient, in spite of the different environment.

20.   UHF coverage is spotty or none-existent in some of the 8.33 candidate States and
      this can create complications for State Aircraft. Close co-ordination with operators
      of State Aircraft and the States concerned will be required to ensure a smooth


21.   The RTC is invited to:

1.    Note the expectation that the need for frequencies will continue to increase;

2.    Agree that meeting the frequency demand is an operational imperative.

3.    Endorse the horizontal expansion of the 8.33 kHz application area as the only
      available solution to meet the forecast frequency demand;

4.    Endorse 31st October 2002 as the date on which the majority of the current
      8.33 kHz exemptions will be withdrawn;

5.    Urge airlines that will have to retrofit aircraft under the new mandate to
      institute the necessary in-house programs with all speed.
                                               IATA European RTC/6                           Agenda Item 12.1.
                                                 Brussels, Belgium           Attachment 1 to Working Paper 12.1.
                                                24-26 October 2000                                      Page 9

                                                                                             Attachment 1.

Figure 1 – Percentage of actual and forecast satisfied demand versus actual and
forecast demand in candidate expansion States (Source: EUROCONTROL)

                 Percentage of Satisfied Neeeds V/S Demand
      Supply /
    demand (%)
                            Expansion Countries

                                                                satisfaction %
                                                                without Horizontal
      60.00                                                     Expansion
      40.00                                                     satisfaction % with
      20.00                                                     Horizontal
                                                                satisfaction % with














                                                                Horizontal and



                                                                Vertical Expansion

   1. The above graph was generated using data from the ICAO EANPG FMG and
      Authorative Representative Body (ARB) frequency management activities over
      the past five years, with the baseline taking account of States’ normal demand per
      type of service, actually achieved implementation rates, States’ stated future
      frequency needs and the possible 8.33 kHz expansion scenarios.

   2. The graph illustrates:
         a. the critical situation before 8.33 kHz implementation (success rate 20%);
         b. the period when the situation will once again become critical (2002-3), if
             nothing is done;
         c. how the 8.33 kHz expansion would provide, for a limited period of time,
             the spectrum release comparable with the initial implementation;
         d. the marginal improvement in spectrum release that may be provided by
             vertical expansion.

   3. In respect of 2/b above, it should be noted that this is not unexpected and is in
      line with the relevant predictions in 1996 as published in the “Plan for the 8.33
      kHz Channel Spacing Implementation in Europe – Edition 2.0”.

   4. In respect of 2/c above, it should be recalled that at the time the initial
      implementation of 8.33 kHz was being planned by the ICAO EANPG
      (EANPG/38-November 1996), it was already recognised that initial
      implementation, limited to the core area of Europe, would provide only a short-
      term solution, with expansion becoming inevitable if the demand for VHF
      channels continued to increase at a rate similar to the increase of traffic demand.
      In fact, this expectation was behind the decision to make the carriage and
      operation of 8.33 kHz capable radio equipment mandatory in the whole of the
      ICAO EUR Region, with temporary exemptions being made available in States
      where the new channel spacing was not yet needed.

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