1

METWSG/2-SN No. 3
/ METWSG/2-SN No. 3
31/3/09

METEOROLOGICAL WARNINGS STUDY GROUP (METWSG)

SECOND MEETING

Montréal, 19 to 21 May 2009

Agenda Item / 6: / Wind shear and turbulence warnings

Progress Report on Wind Shear and Turbulence Warnings

(Presented by the Secretary)

SUMMARY
This study note provides an overview of the tasks of the group that concern wind shear and turbulence warnings and a review of the actions taken since the last meeting of the group.

1.INTRODUCTION

1.1This study note summarizes the progress made regarding wind shear and turbulence warnings since the METWSG/1 Meeting and provides suggested courses of action where necessary.

2.discussion

2.1Low-level wind shear detection in the approach/take-off paths

2.1.1The group will recall that Action Agreed 1/5 from the METWSG/1 Meeting sought the development of a proposal for the development of standard phraseologies for wind shear alert information in the approach and take-off/climb-out areas. Furthermore, it was noted by that meeting that any proposal would need to be coordinated appropriately as an air traffic management (ATM) procedure and would have to respect the editorial policy of the Procedures for Air Navigation Services — Air Traffic Management (PANS-ATM, Doc4444) in that it should consist of no more than two or three standard phraseologies.

2.1.2The group may wish to note that a set of standard phraseologies was agreed and presented in detail in SN/9 with those limited additions to Doc 4444 presented in the Appendix. Thegroup is invited to agree the following action on the strength of the work carried out:

Agreed action 2/x — Phraseologies relating to wind shear for proposed inclusion in the PANS ATM (Doc 4444)
That, the Secretary forward the standard phraseologies included in the Appendix for inclusion in the PANS ATM (Doc 4444) following the appropriate consultation process.

2.1.3The group may wish to note that further discussion relating to the potential for additional entries relating to the distinction between forecast and observed wind shear events and hence the use of a semi-automatic system took place. Further information in this regard is described in SN/10 and SN/13. The group may wish to consider whether such phraseology should be included bearing in mind the need for brevity and the potential requirements for information regarding semi-automatic systems of this nature.

Provisions related to low-level wind shear

2.1.4The group will recall that additional material was provided for the Manual on Low-Level Wind Shear (Doc9817) at the METWSG/1 Meeting, which has subsequently been included in the manual on 26 September 2008, and that the ICAO wind shear posters were also updated by the group in order to assist in the observing and reporting of low-level wind shear. The group may wish to note that the task in the work programme of the group relating to the observing and reporting of low-level wind shear has remained open with a view to updating Doc 9817 to make it compatible with Amendment 75 to Annex 3. The update will take place once Amendment 75 has been adopted and it is proposed that the task be deleted following this action since no direct proposals are expected relating to this task in the foreseeable future. The group is invited to agree the following action:

Action agreed 2/x — Update of the Manual on Low-Level Wind Shear(Doc 9817) and deletion of the work programme task relating to the observing and reporting of low-level wind shear
That,
a)the Secretary update the Manual on Low-Level Wind Shear (Doc 9817) to make it compatible with Amendment 75 to Annex3 following its adoption; and
b)work programme task 5 relating to the observing and reporting of low-level wind shear should be deleted on completion of a) above.

2.2Improved forecast algorithms for turbulence for use in SIGMET

2.2.1The group may wish to note that the Air Navigation Commission (ANC), in disbanding the Meteorological Information Data Link Study Group (METLINKSG) during the seventh meeting of its 178th Session on 12 June 2008, agreed that one of two additional tasks allocated for the Secretariat to be assisted by the METWSG would relate to improved forecast algorithms for turbulence for use in SIGMET.

2.2.2The group may wish to note that the automatic generation of turbulence forecast information for use in the world area forecast system (WAFS) has been under consideration by the World Area Forecast System Operations Group (WAFSOPSG) since its inception following the MET Divisional Meeting (2002). This has led to the introduction of gridded forecasts of clear-air and in-cloud turbulence by the WAFC as a part of draft Amendment 75 to Annex 3.

2.2.3The group may wish to agree that a study should be undertaken to consider whether the algorithms used to automatically generate the WAFS forecasts of turbulence could provide some benefit in the case of SIGMET. Such a study should take advantage of the knowledge gained by the WAFC and the contributions made by other members of the group where similar work has been undertaken and should focus on the possibility of providing guidance or the need for provisions to assist in this regard. The group may wish to agree the following action:

Action agreed 2/x — Ad hoc group to consider the use of turbulence forecast algorithms in the automatic generation of SIGMET
That, an ad hoc group consisting of Nigel, Steve, Patrick, ………should study the possibility of using turbulence forecast algorithms for the use in SIGMET and produce a report in time for the third meeting of the group for its consideration.

2.3Automated turbulence warnings in the approach/landing areas

2.3.1The group may wish to note that the ANC also referred a task for consideration by the Secretariat with the assistance of the METWSG relating to automated turbulence warnings in the approach/landing and take-off/climb-out areas using data from aircraft or ground based remote sensing equipment (2.2.1 above refers).

2.3.2The group may wish to agree that a study should be undertaken to consider whether the knowledge gained from the installation of automatic or semi-automatic systems at a small number of aerodromes could be used to develop guidance material or provisions to assist States in the future development of such systems. The group may wish to agree the following action:

Action agreed 2/x — Ad hoc group to consider the use of automatic turbulence warning systems in the approach/landing and take-off/climb-out areas
That, an ad hoc group consisting of CM, Steve …….. should study the possibility of using an automatic turbulence warning system in the approach/landing and take-off/climb-out areas.

3.action by the metwsg

3.1The METWSG is invited to:

a)note the information in this paper; and

b)decide on the draft action proposed for the group’s consideration.

— — — — — — — —

A-1 / METWSG/2-SN No. 3
Appendix A
METWSG/2-SN No. 3
Appendix

APPENDIX

12.3.1.7 METEOROLOGICAL CONDITIONS / a) …
…
… for alerting approach or departure aircraft to microburst / p)[CAUTION] [RUNWAY(number)] MICROBURST[ALERT] [MINUS (orPLUS)] [(number) KNOTS (or KILOMETRES PER HOUR)] [LOSS (orGAIN)] [(number) MILE] [ON] [FINAL][APPROACH (orDEPATURE)] [RUNWAY]
Note 1.Either [CAUTION] or [ALERT] should be used.
Note 2. Either
[(number) MILE][FINAL (or DEPARTURE)][ON RUNWAY]
or
[ON][FINAL APPROACH (or DEPARTURE)][RUNWAY]
should be used
Note3.Either [MINUS (or PLUS)] or [LOSS (or GAIN)] should be used for the signof the microburst magnitude.
… for alerting approach or departure aircraft to significant wind shear / q) [CAUTION] [RUNWAY(number)] WIND SHEAR [ALERT] [MINUS (orPLUS)] (number) KNOTS (orKILOMETRES PER HOUR) [LOSS (orGAIN)] [FORECAST (or REPORTED)] [(number) MILE] [ON] [FINAL] [APPROACH (orDEPARTURE)] [RUNWAY]
Note 1.Either [CAUTION] or [ALERT] should be used.
Note 2. Either
[(number) MILE][FINAL (or DEPARTURE)][ON RUNWAY]
or
[ON][FINAL APPROACH (or DEPARTURE)][RUNWAY]
should be used
Note3.Either [MINUS (or PLUS)] or [LOSS (or GAIN)] should be used for the signof the wind shear magnitude.
Note4. [FORECAST] could be used, as an option, for a wind shear alert generated by a forecast algorithm rather than detection based on ground-based, wind shear detection or remote-sensing equipment.
Note5. [REPORTED] could be used, as an option, for a wind shear alert corroborated by pilot report(s). If this reported wind shear alert happens to be generated by a forecast algorithm (see Note 4 above), [FORECAST] should be omitted in this case.

— END —