SIXTH MEETING

SADIS OPERATIONS GROUP

(Paris, France, 28 May to 1 June 2001)

EXECUTIVE SUMMARY

1.	Introduction

1.1	The sixth meeting of the SADIS Operations Group (SADISOPSG) was held in the European and North Atlantic (EUR/NAT) Regional Office, Paris, 28 May to 1 June 2001. The meeting was attended by 31 experts from eleven States, the Chairman of the Meteorological Communications Group (MOTNEG), the focal point of the EUR OPMET Bulletin Management Group (BMG) and three international organizations (the Agency for the Safety of Aerial Navigation in Africa and Madagascar (ASECNA), the International Air Transport Association (IATA) and the World Meteorological Organization (WMO)).

1.2	Mr. T.J. Potgieter, the member from South Africa, was Chairman of the meeting.

2.	Annual statement of SADIS operational efficacy and update of SADIS inventory

2.1	The group reviewed the operation of SADIS during 2000/2001 based on: responses from fifty States to the annual questionnaire, the annual management report from the SADIS provider States, and input from IATA. The group concluded (Conclusion 6/5) that the SADIS broadcast had continued to meet the operational requirements during the period under review. As is customary, this statement would be sent to the Chairman of the SADIS Cost Recovery Administrative Group (SCRAG). The group regretted that the number of replies had not markedly increased from the previous year. It was concluded that, in order to improve the response rate of the annual SADIS questionnaire, ICAO would place the questionnaire on its SADISOPSG web-site and send the questionnaire, in addition to States and users, also to SADIS focal points (Conclusion 6/2). With regard to the format of the analysis used by the SADIS provider State the group considered that no major changes were required. However, the group was of the opinion that, in order to facilitate the assessment of the SADIS efficacy, the SADIS provider State would include in the analysis of the questionnaire statistics related to the previous year (Conclusion 6/3).

2.2	Concerning the detailed results of the analysis, the group was encouraged by the fact that the number of reports of serious difficulties with SADIS very small aperture terminal (VSAT) had decreased over the past year. With regard to administrative messages, the group felt that their availability would be improved if the administrative messages, including those related to unplanned outages, would be placed on the UK MET Office SADIS web-site by the SADIS provider State (Conclusion 6/4).

2.3	The group updated the SADIS inventory 2001/2002 to take account of decommissioned items of equipment and the enhanced two-way requirements (Conclusion 6/6). The updated inventory would be forwarded to the Chairman of SCRAG.

2.4	With regard to the SADIS implementation, the group noted that the system continued to expand in 2000/2001, with ninety-two Contracting States and one other location now operating a total of 131 SADIS VSAT receivers.

3.	Maintenance of the current SADIS broadcast and organization of the flow of OPMET message traffic

3.1	The group reviewed the current Annex 1 to the SADIS User Guide. It was noted that no formal requests for additional OPMET information had been received from other groups and hence it was assumed that the current Annex 1 was satisfactory.

3.2	The SADISOPSG recalled that it had supported the EUR OPMET update of requirements procedure, in principle pending some clarifications, which have since been provided by the Meteorological Communications Group (MOTNEG). The group reviewed the revised flow diagram and found the updated EUR OPMET update procedure satisfactory (Conclusion 6/8). Since these procedures had proved to be efficient, it was suggested that the APANPIRG, APIRG and MIDANPIRG should give consideration to introducing the EUR OPMET update procedure in their respective regions (draft Conclusion).

3.3	With regard to NOTAMs for volcanic ash and ASHTAMs, the group was aware of the problem to route these messages to some of the volcanic ash advisory centres (VAACs) due to aeronautical fixed telecommunication network (AFTN)/global telecommunication system (GTS) interface difficulties at some switching centres. The group noted that a series of tests involving a selection of international NOTAM Offices (NOFs) sending NOTAMs for volcanic ash and ASHTAMs to all VAACs and to the London switching centre for uplink on SADIS using a "dummy" WMO header would be conducted during summer 2001.

3.4	It was recalled that the group had agreed that tropical cyclone advisories should be disseminated on SADIS. However, at the present time no tropical cyclone advisories (with the data designator "FK") were disseminated; the SADIS broadcast did include tropical cyclone advisories intended for general use (with the data designator "WT"); however, these bulletins were not an aviation requirement. Therefore, the group agreed that the SADIS provider State should include on the SADIS broadcast, as a matter of urgency, the tropical cyclone advisories issued by the tropical cyclone advisory centres (TCAC), with the data designator "FK" (Conclusion 6/9).

4.	Development of the SADIS

4.1	The discussions of the group were based on reports from the Rapporteurs of its Two-way Operational Clearance Team, Gateway Working Group and Strategic Assessment Team.

Enhanced two-way capability

4.2	The group was aware that APIRG had proposed Nairobi as a site for the fifth available "enhanced" SADIS two-way VSAT station. Kenya made a formal offer to host this VSAT station. After examining Kenya's offer thoroughly, the SADISOPSG concluded that the fifth two-way VSAT station should be installed in Nairobi with the understanding that Kenya would be responsible for the costs resulting from the transportation and installation of the two-way VSAT station in Nairobi (Conclusion 6/11).

4.3	It was noted that the three original SADIS two-way VSAT sites (London, Pretoria and Zurich) had been upgraded to "enhanced" capability and these stations would be prepared for the final trials called for by SADISOPSG Conclusion 5/13. The group agreed that, in view of the move of the UK MET Office to Exeter, the SADIS provider State should arrange for the final two-way trials to be completed by April 2002 at the latest, with the participation of all the operational two-way VSATs with "enhanced" capability installed by this time; on conclusion of these two-way trials, the SADIS provider State would offer the components of its two-way station as spare parts for the existing two-way stations in Pretoria and Zurich (Conclusion 6/10). ASECNA indicated that every effort would be made to start the installation before December 2001 for completion in time for the final two-way trials planned for early 2002. The fifth VSAT station in Nairobi, if implemented by that time, would also take part in these trials.

SADIS Gateway Function

4.4	The Rapporteur of the SADISOPSG Gateway Working Group reported to the group on progress in the letting of contract and implementation of the SADIS gateway function. It was indicated that the provisional dates for acceptance testing and operational service were January 2002 and October 2002, respectively.

4.5	The group was also briefed by the Rapporteur of the SADISOPSG Gateway Working Group on progress made in the development of the SADIS Gateway Operations Handbook. An overview of the draft version of the handbook was presented to the group. It was noted that the handbook would not be completed until the contract for the gateway function had been awarded.

Strategic assessment of SADIS requirements

4.6	The Rapporteur of the SADISOPSG Strategic Assessment Team provided a report on the activities of the team. The group reviewed the report presented as a series of tables and concluded that the completed SADIS strategic assessment tables should form the basis for the future development of the SADIS (Conclusion 6/12).

Decoding WAFS data in the GRIB and BUFR code forms

4.7	With regard to the use of the WMO BUFR and GRIB code forms for the transmission of WAFS SIGWX and wind/temperature forecasts in numerical format, the group felt that from the SADIS point of view this development was of considerable interest because it could release substantial bandwidth which could be utilized for other purposes, as necessary. The importance of training in this area was emphasized and the group invited the SADIS provider State to consider organizing, in coordination with WMO, ASECNA and ICAO, seminars on decoding WAFS data disseminated in the GRIB and BUFR code forms (Conclusion 6/13).

SADIS cost recovery

4.8	The group noted that the ICAO Council had decided that from 1 January 2001 the recovery of the costs of the SADIS from users of the service would be mandatory (except for the "least developed countries (LDC)"). In the light of this decision, a specific issue was raised, i.e. how to avoid that a VSAT station dealing with the development of software for SADIS and located in a State which has decided not to participate in the cost recovery would be switched off. The group felt that this was an important issue and requested the Chairman of the SADISOPSG to bring to the attention of the Chairman of the SCRAG the importance of the continued operation of VSAT stations used exclusively for the technical development of SADIS, no matter whether the State participates in the cost recovery scheme (Conclusion 6/14).

4.9	In view of the introduction of the mandatory cost recovery in 2001, the group was of the opinion that the composition of the group should be reviewed. In particular, it was felt that it would not be appropriate for States not participating in the cost recovery and hence not receiving the SADIS broadcast to be members of the SADISOPSG. In this regard, the group invited the APANPIRG, APIRG, EANPG and MIDANPIRG to review the composition of the SADISOPSG (draft Conclusion).

Maintenance and repair of SADIS receiving equipment

4.10	The SADISOPSG emphasized the importance of training technicians for maintaining and repairing SADIS receiving equipment. It invited the SADIS provider State to approach Astrium to investigate whether consideration could be given to expanding the list of authorized personnel to undertake maintenance to include skilled technicians in selected SADIS user States and study the possibility of organizing training events on the maintenance of SADIS receiving equipment for skilled technicians in the AFI Region (Conclusion 6/15).

SADIS internet-based FTP/HTTP service for back-up

4.11	The SADIS provider State informed the group of a SADIS internet-based FTP/HTTP service. It was emphasized that the internet service could only be considered as a back-up since, in accordance with ICAO provisions, the WAFS data and products were to be disseminated through the ICAO Aeronautical Fixed Service (AFS) using SADIS and ISCS. The web-site would be password protected. The group invited the SADIS provider State to implement the SADIS internet-based FTP service as a back-up to the SADIS broadcast with the understanding that this service would be provided only to States and users authorized to receive SADIS or ISCS broadcasts and without any additional cost to States (Conclusion 6/16).

Back-up link for alphanumeric data on SADIS

4.12	The group recalled that there had been a back-up link for OPMET messages between Bruxelles and Bracknell to be used in case the Heathrow AFTN switch became non-operational. The back- up circuit had been removed on 1 April 2001 as a result of changes which had taken place in Belgium. In view of the very low likelihood of failures at the Heathrow switching centre which had been refurbished with the new AFTN/CIDIN message switch, the group concluded that the establishment of a back-up link would not be justified (Decision 6/17).

5.	SADIS User Guide and amendment process

5.1	The group approved the proposed amendments to the Second Edition of the SADIS User Guide. It was noted that there would be additional amendments of a purely editorial nature. The group agreed that those amendments would be forwarded to the Secretary by 31 July 2001.

5.2	The group was also informed about the changes in the UK MET Office SADIS web-site, including the introduction of a semi-automated way of updating Annex 2 and 3. The efforts by the SADIS provider State and Belgocontrol in this regard were acknowledged by the group.

6.	Future work programme

The group reviewed and updated its work programme and executive summaries for the tasks in the work programme.

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