FOURTH MEETING

SADIS OPERATIONS GROUP

(Paris, 7 to 11 June 1999)

EXECUTIVE SUMMARY

1.	Introduction

1.1	The fourth meeting of the SADIS Operations Group (SADISOPSG) was held in the European and North Atlantic Regional Office, Paris from 7 to 11 June 1999. The meeting was attended by twenty-three experts from States and 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 elected Chairman.

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

2.1	The group reviewed the operation of the SADIS during 1998/99 based on responses to a questionnaire from forty-eight SADIS users and the management report provided by the SADIS provider State and service provider, and concluded (Conclusion 4/5) that the operational efficacy of SADIS had continued to be satisfactory, meeting all operational requirements. As is customary, this statement on SADIS operational efficacy will be sent to the Chairman of the SADIS Cost Recovery Administrative Group for the EUR Region (E)SCRAG)

2.2	Amendments were made to the SADIS inventory in order to reflect the enhancement of the SADIS two-way VSAT capability (Conclusion 4/6).

2.3	The response to the questionnaire indicated that some States were still not aware of the SADIS Admin Messages which were broadcast, probably because their data/processing systems did not recognize the headers. For this, and other reasons, the group considered it necessary to further advertise these messages (Decision 4/1 and Conclusion 4/2) and to recommend to the planning and implementation regional groups (PIRGs) that SADIS user States be requested to nominate a SADIS operational focal point for the State who would provide direct contact for day-to-day operational matters related to SADIS (draft Conclusion 4/..).

2.4	It was agreed that the replies to future annual SADIS efficacy questionnaires should be subjected to an automated analysis under the direction of the SADISOPSG Operational Efficacy Questionnaire Assessment Team (Decision 4/4).

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

3.1	The group reviewed the current Annexes 1 and 2 in the SADIS User Guide, containing lists of the required OPMET data and available OPMET data on SADIS, respectively, and proposals by the SADIS provider State and the EUR Bulletin Management Group (BMG) for a replacement table for Annex 2 and the inclusion of a new table for Annex 3. It was agreed that, as the preparation of tables proposed for Annexes 2 and 3 by the BMG were automated and the tables updated monthly, these would be the most useful for the SADIS User Guide (Conclusion 4/7). It was noted that Annex 1 represented the formal list of OPMET data that States had explicitly, or implicitly, agreed would be transmitted on SADIS. In view of this, ICAO would retain direct control of Annex 1 and it would not be made available on the SADIS web site.

3.2	The group reviewed the EUR OPMET update procedure, in so far as it concerned SADIS, noting that, in accordance with European Air Navigation Planning Group (EANPG) /40 Conclusion 40/36, the EUR OPMET update procedure was expected to be brought to the attention of the other regional groups for consideration. While the EUR OPMET update procedure was approved, in principle, it was agreed that the flow diagram should be amended to reflect the responsibilities of the SADISOPSG in respect of distribution of OPMET data on the SADIS broadcast, and the use of the terminology "requirements accepted" or "not accepted" would be clarified to distinguish day to day operational "changes" and substantive operational requirements in terms of Annex 1 to the SADIS User Guide (Conclusion 4/8). In this latter regard, the group noted the ICAO procedure whereby amendments could be effected to Annex 1 to the SADIS User Guide, and that this procedure should be referred to, as appropriate, in the proposed EUR OPMET procedures.

4.	Development of the SADIS

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

4.2	It was noted that contractual action had been completed with Matra-Marconi and the upgrade of the hub to support the enhanced SADIS two-way applicability was expected to be completed in July 1999. The most pressing issue was the installation of the two enhanced two-way very small aperture terminals (VSATs) , held in the inventory for trial purposes, in two States prepared to conduct the necessary trials. The upgrade of the three existing two-way sites in London, Pretoria and Zurich also had to be completed. It was agreed that confirmation should be sought from Switzerland that they were prepared to undertake the enhanced two-way trials (Conclusion 4/10) and the situation vis-à-vis Singapore clarified. It was noted that the use of Moscow for a two-way test site would be proposed at the next Meteorological Group (METG) meeting in October 1999. The group also agreed that, because most States will be involved with Y2K testing and equipment replacement, the enhanced two-way test programme should not be started until 2000.

4.2	The group discussed the first SADIS BUFR trial (l March to 14 April 1999) which had been conducted primarily to ascertain the effect, if any, on the existing broadcast. It was noted that the OPMET, GRIB and T4 chart transmissions were unaffected. However, as the trial progressed, problems were encountered by SADIS users not taking an active part in the trials. It transpired that the BUFR messages were being retained in the buffer memory which overflowed and shut down the system pending a reboot. The group considered options to resolve the problem and agreed that the next test should first be undertaken off-line with the GRIB data transmitted as part of the T4 bit stream on PVC3. If this proved successful then a test would be conducted on-line.

4.3	The main technological development of interest to the group at this meeting concerned the advantages to users of providing TCP/IP protocols on the SADIS. It was noted that the TCP/IP interface could be provided by either a) the addition of an external converter between the VSAT receiver and the user workstation; or b) the replacement of the FRAD card in the VSAT. The group agreed that the SADIS provider State should obtain costs for both options from Matra-Marconi and, assuming no unforeseen problems or disadvantages were disclosed, the information could be provided to user States to enable them to consider whether they wished to take advantage of the TCP/IP protocols (Conclusion 4/13).

4.4	The group noted that a first draft of the SADIS strategic assessment tables had been developed by the SADIS Strategic Assessment Team which would be considered, and amended as necessary, by the relevant ICAO regional groups. The terms of reference of the Strategic Assessment Team were revised accordingly (Decision 4/14).

4.5	The group was informed that the contract for the SADIS Gateway had been put out to European Community tender, and the contract award was expected by the end of June 1999. The latest version of the SADIS Gateway Technical Requirements which included additional automatic error correction procedures, as approved by the MOTNEG, were also approved by the SADISOPSG (Conclusions 4/15 and 4/16).

5.	SADIS User Guide and amendment process

5.1	The main change to the SADIS User Guide concerned the inclusion of two new annexes (2 and 3) as reported under paragraph 3.1 above). It was also agreed that Annexes 2 and 3 would be made available on the SADIS web site (Conclusion 4/17).

6.	Future work programme

6.1	The group reviewed and updated its work programme and executive summaries.

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