NINTH MEETING DISPLAY IN ATS UNITS. (Presented SUMMARY

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1 AMOFSG/9-SN No /8/11 AERODROME METEOROLOGICAL OBSERVATION AND FORECAST STUDY GROUP (AMOFSG) NINTH MEETING Montréal, 26 to 30 September 2011 Agenda Item 6: MET informationn to support ATM UPDATING OF INFORMATION PROVIDED BY DISPLAY IN ATS UNITS AND PRACTICES USED TO UPDATE ATIS (Presented by Michel Leroy) SUMMARY This document is a summary report on practices for updating local reports and ATIS from the group s members. After recalling some rules of Annex 3 concerning displays and local reports, it highlights some missing recommendations in case of fully automated systems. It proposes a recommendation in case of fully automated system. 1. ICAO ANNEX 3 REQUIREMENTS 1.1 ICAO Annex 3 Meteorological Service for International Air Navigation, Appendix 3, asks for displays in the meteorological station and ATS units, for surface wind ( ), RVR ( ), QNH/QFE ( 4.7.1). Displays are also recommended for visibility, height of cloud base, air temperature and dew-point temperature. The minimum update frequency of the displays is not defined. The Manual on Automatic Meteorological Observing Systems at Aerodromes (Doc 9837) indicates in its that a period longer than 1 minute must be avoided. 1.2 Annex 3 requires local routine reports to be made at intervals of one hour or at intervals of one half-hour. Intermediate local special reports are made on defined criteria. 1.3 Agreement between the meteorological authority and the appropriate ATS authority, local special reports need not be issued in respect of any element for which there is a display in the local air traffic services unit (appendix 3, a). 1.4 Annex 11, requires to extract the routine and special reports for ATIS. (5 pages) AMOFSG.9.SN en.docx meteorological information from the local

2 AMOFSG/9-SN No DISCUSSION 2.1 The type of displays for the different parameters is not defined. Considering the known operational systems, it can be dedicated displays, one for each meteorological element. It can be also a video display combining all the meteorological elements. This latter solution is usually less expensive than individual displays. 2.2 When a combined video display is used, it is generally updated at least every minute, for the automatic measurements. This is necessary to follow the requirements of Annex 3 ( , , 4.7.1, etc.). Manual observations are updated every hour or half-hour and upon local special criteria. In this case, local displays/reports are updated every minute for automatic measurements and at the specified frequency for manual observations. 2.3 Voice-ATIS and/or D-ATIS is usually updated at reception of each local routine and special report. Each individual ATIS message is identified by an alphabetic letter. When establishing the communication with the ATS unit, the aircraft acknowledges the ATIS message (by its letter). So, both the aircraft and the ATS unit have the same meteorological reference. The controller may communicate to the aircraft the meteorological elements having changed since the last common ATIS message. The most recent RVR(s) is(are) systematically communicated. 3. SOME PRACTICES OF MEMBERS 3.1 See the appendix to this paper. 4. QUESTIONS AND MISSING RECOMMENDATIONS 4.1 With a fully automated system, when all the (automatic) measurements of a local report are updated every minute, what is a local report? The one minute message or a message selected every 30 minutes and on special conditions? In case of one minute message, the rules for updating the ATIS messages are not clearly defined. 4.2 The requirements for displays with implicit frequent updating and for local reports typically updated every half-hour were probably drafted at a period where local reports were manually written. The required displays for wind, RVR and QNH/QFE were the only technical mean for frequently updating the information. The current situation where a frequent update of automatic parameters is done may cause problems for updating of the ATIS messages. 4.3 ATIS is supposed to be updated on reception of a local routine or special report. This explains that local reports should not be updated too fast for ATIS. Does it mean that information for displays should not be extracted from local reports? Or that local reports could be issued every minute, in which case the rules for updating ATIS messages should be adapted? 4.4 Does an update of ATIS every minute would be acceptable by users (pilots and air controllers)?

3 - 3 - AMOFSG/9-SN No RECOMMENDATION 5.1 With automatic systems, there are reasons for updating the meteorological information frequently (i.e. every one minute). It is required under the requirement and recommendations for displays. But local reports are defined to be reported at a slower frequency (typically every half-hour for routine reports). And it is necessary to keep criteria to update ATIS (30 minutes and special conditions), except is updating ATIS every minute could be acceptable. 5.2 In case of fully automated systems, local reports could be updated every minute, with an additional indication (flag) for updating the ATIS: 30 minutes or special condition encountered. 6. ACTION BY THE GROUP 6.1 The group is invited to : a) review and comment upon the contents of this paper; b) clarify the updating frequency of local reports, in case of fully automated systems and/or when local reports are used for local displays.

4 AMOFSG/9-SN/26 Appendix APPENDIX Country Local displays Local reports ATIS update Remarks Australia* METAR AUTO, SPECI AUTO are used as local reports Belgium Real time display updated every 1 minute for automatic measurements (12 seconds for 2min average wind values). At least 30 minutes from a human observer input (visibility, clouds & present weather) Local report every 30 minutes, containing the values for all locations Selection of relevant values in relation to the runway(s) in use China Updated from METAR every 30 minutes. Also use of SPECI and SPECIAL France Real time display updated every 1 minute for automatic measurements: common display on a video screen + specific displays for wind and pressure. Netherlands Real time display on ATC systems of wind, visibility and RVR updated every 1 minute for automatic measurements (12 seconds for wind). The ATC systems additionally display the (AUTO) METAR and (auto) local routine and (auto) local (special) reports. Local report = real time display, updated every 1 minute, for all automatic measurements (including Present Weather, clouds, visibility). Human observation updated every 30 minutes and when special conditions (Auto) local reports every 30 minutes (H+25, H+55) proposed by the system and corrected by the observer or confirmed by the meteorologist. Information on windshear and low level temperature inversion are added if appropriate, as well as REMARKs for several items. A From 30 minutes to 2 hours, on the decision of the air controller: manual decision and systematic audio monitoring. SPECIAL conditions are highlighted. An (auto) local special report is issued when update criteria are met. Depending on the criterion, either the KNMI system proposes a local special report, the observer on site or the meteorologist in the Bilt triggers the update. These criteria are determined by local agreement. Belgocontrol will stop issuing Special MET Reports in accordance with a in Appendix 3 of ICAO Annex 3 (real time displays available) TREND forecast is also provided to ATIS in some airports in China ATIS is systematically controlled (listened) by the air controller, before issuance. Note that other non meteorological items are initiators for an ATIS update, such as a change of runway. Specifically for Schiphol airport, two local routine and local special reports exist, one for arrival and one for departure. This means two

5 AMOFSG/9-SN No. 26 Appendix A-2 Country Local displays Local reports ATIS update Remarks TREND is added to each report. UK Local report every 30 minutes (H+20, H+50). Automatic SPECIAL for pressure and temperature, otherwise human observer responsible for SPECIAL report (for cloud amount / height, RVR present weather and visibility) and initiating an ATIS update USA* METAR AUTO, SPECI AUTO are used as local reports The human observer or meteorologist remains responsible for issuance of (auto) local routine and (auto) local special reports and by doing so initiating an ATIS update. Then, the ATIS is updated automatically via an electronic voice. 30 minutes and after a special report. * indicates information coming from the knowledge of the author. To be confirmed by country members. separate ATIS broadcasts exist, one for arrival and one for departure, each with slightly different requirements. RVR information is not available in the actual ATIS broadcast. In situations of RVR conditions the ATIS broadcast contains the message: For RVR consult ATC on local frequency. When there are no MET observers present and the system is automated then the ATIS message is only updated using output from the sensors available. END