Aviation is today the safest mode of mass transportation. It carries annually 1.5 billion passengers and 28 million tons of cargo. The annual growth rate is in the order of 5%. In addition, aviation contributes significantly to world peace and prosperity. It creates unmatched opportunities for travel, recreation and business, and directly supports 28 million jobs worldwide. It brings countries together and increases their knowledge and appreciation of each other.

Civil aviation has taken its place as one of the most important contributors to the wealth and welfare of all peoples in all regions of the world. Like telecommunications, it has helped to bring the people of the world together into an actual global village. Almost every place in the world can now be reached in less than 24 hours using scheduled air transport.

Safety and efficiency in aviation result from exemplary international cooperation and consensus on the part of all members of the world aviation community in the development and implementation of technical standards for the design and construction of aeronautical products and infrastructure.

The International Civil Aviation Organization (ICAO), a specialized agency of the United Nations, has been developing standards since 1945. An important aspect of these standards relates to aeronautical radio communication, radionavigation and surveillance (radar) systems and equipment, installed on aircraft or on the ground. Aviation safety demands the availability and security of adequate and well-protected radio-frequency spectrum. ICAO has been actively working with ITU since 1947 to ensure that decisions related to spectrum management will secure the long-term availability of radio-frequency spectrum for aviation use.

With respect to the development of international agreements relating to the use of the RF spectrum, the leading role of ITU is indispensable for the equitable distribution of this limited spectrum amongst the various services. Traditionally, this distribution is internationally agreed to at ITU world radiocommunication conferences through the adoption of amendments to the ITU Radio Regulations.

The ITU has recognized the needs of the aviation community and the Radio Regulations provide the internationally-agreed framework for aeronautical spectrum within which ICAO develops its standards. Thus, the long-term availability and stability of spectrum allocations for aeronautical services is essential to ensure long-term availability and stability of the necessary communication, navigation and surveillance (radio location) services. In particular, amendments to the allocations for aeronautical services must be carefully coordinated to avoid adverse effects on aviation safety.

Since the early 1990s, ICAO has been developing standards for the future communications, navigation and surveillance (CNS) systems necessary to modernize the aeronautical infrastructure and to support the growth of air transport. These systems are being developed within the spectrum that was available for aviation at that time, and they are expected to provide the new means for radio communication and radio navigation and surveillance necessary to cope with the projected increase in air traffic. They are also expected, in the long term, to reduce overall spectrum requirements for aviation.

Introduction of new CNS systems is taking place over a lengthy transition phase to ensure that new systems are designed and validated before being put into full operation. The complexity of some of these systems has made the transition period longer than originally foreseen. Before the new systems can replace the current ones, a careful assessment of safety aspects has to take place. This transition may extend over a period of more than 10 years and require parallel operation of both current and new systems.

The loss of protection for aeronautical spectrum to satisfy the demands of certain interests for more spectrum cannot be further accommodated without affecting safety, efficiency and regularity of international aviation services. A last minute proposal at WRC-97, to share with the mobile-satellite service (MSS) the 1559 – 1567 MHz band allocated to the radionavigation-satellite service (RNSS), is an example of actions that compromise safety of aviation. The potential of adverse effects on aeronautical navigation resulting from the implementation of that proposal are now clearly understood and ITU-R has concluded that sharing between RNSS and MSS cannot be supported in any portion of the band.

ICAO’s concern with the introduction of new allocations in the radio-frequency spectrum is primarily focused on the protection of the current aeronautical services. Introduction of new services and systems, whether these are for aeronautical or non-aeronautical purposes, need to recognize the protection necessary to the safety of aviation. Nevertheless, aviation has significantly contributed over the years to overcome difficulties stemming from the increased requirements for radio-frequency spectrum by various radio services. In some areas, the increased demand for spectrum has been accommodated by establishing compatibility criteria through the development of ITU-R Recommendations that were acceptable for aviation requirements.

On the basis of the agenda for WRC-2000, ICAO has identified the following main areas of concern:

In the course of the review of the spectrum requirements for IMT-2000, consideration was given by some parties to the use of the frequency band 2700 - 2900 MHz by the mobile service. This band is extensively used on a global basis for primary radar systems that will continue to be an essential tool in air traffic control to assure aircraft separation and collision avoidance. ITU-R Working Party 8B is addressing the protection requirement for radar systems which are to be used in any future study on the feasibility of the proposed allocation.

Proposals are circulating to review, at a future WRC, the use of the HF bands by the Aeronautical Mobile Service aviation and other radio services, including the possibility to revise Appendix 27 to the Radio Regulations. At present, there is no need for a review of the use of the HF bands by the aeronautical mobile (R) service identified. ICAO is developing plans to introduce an HF data link in these bands.

The matter of the introduction of a generic allocation to the mobile-satellite service in the frequency band 1559 - 1567 MHz has already been mentioned above. The growing opposition to this proposal demonstrates the need for thorough analysis and studies on the feasibility of any proposed sharing scenarios to be completed, prior to taking any decision on an allocation, in particular where a safety service is affected.

On the matter of the introduction of a generic allocation to the mobile-satellite service in the 1.5/1.6 GHz bands and the removal of the exclusive allocation to the aeronautical mobile satellite (R) service in 1997, ICAO is still deeply concerned about the future availability of spectrum for aeronautical satellite communications as well as the validation of the identified protection mechanisms. Proposals from some administrations to improve access of the aeronautical service to this band go some way towards addressing these concerns.

At WRC-95 and WRC-97, a significant amount of discussion concentrated on an allocation to the fixed-satellite service for feeder links for non-geostationary orbit (non-GSO) satellite systems in the frequency range 15.43 - 15.63 MHz. Because of difficulties with the sharing of a variety of airborne and ground-based radionavigation systems and equipment, this allocation should be limited to non-GSO MSS feeder links for which advanced publication has been received by the ITU Radiocommunication Bureau prior to the end of WRC-2000.

Of great concern to aviation is the issue of allocations to the radionavigation-satellite service in the frequency bands between 1 - 6 GHz. In particular, the US-based global positioning system (GPS) and the European-based Galileo system are seeking global allocations in bands used for existing radionavigation systems, such as the distance measuring equipment (DME) and microwave landing system (MLS).

ICAO's prime goal is to ensure the continuing availability of spectrum for the existing systems. Spectrum for the future RNSS systems can only be made available if it can be demonstrated that these future systems do not impair or restrict unacceptably the operation of the existing system. With respect to the MLS band (5030 – 5150 MHz), the Conference Preparatory Meeting stated that simultaneous co-frequency and co-coverage operation of MLS and RNSS is not feasible.

It is ICAO's view that an allocation to RNSS cannot be made in this band in the light of the spectrum requirements for MLS. These requirements were reviewed at WRC-95 and will most probably be placed on the agenda for the next WRC. With respect to the DME band, an allocation to RNSS is not without problems. Aircraft reception of RNSS signals is interfered by ground-based DME transponders operating on the same frequencies as RNSS. Furthermore, the satellite-based emissions affect the reception of DME signals on board an aircraft.

Although special measures may be taken to achieve compatibility between RNSS and DME, final decisions should only be taken after the relevant studies are completed. The action taken by this conference should therefore be of a preliminary nature, and further studies, addressing all aspects on the compatibility between RNSS and the aeronautical radionavigation service, should be recommended. In order to limit the adverse effects on the operation of existing systems, an RNSS allocation should be limited to the smallest possible portion of the DME band and, in any case, should not exceed a total of 48 MHz.

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ICAO was created in 1944 to promote the safe and orderly development of civil aviation in the world. A specialized agency of the United Nations, it sets international standards and regulations necessary for the safety, security, efficiency and regularity of air transport and serves as the medium for cooperation in all fields of civil aviation among its 185 Contracting States.