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METWSG/1-SN No. 7
/ METWSG/1-SN No. 7
12/10/07

METEOROLOGICAL WARNINGS STUDY GROUP (METWSG)

FIRST MEETING

Montréal, 20 to 22 November 2007

Agenda Item / 7: / Amendments to provisions related to wind shear warnings and alerts
7.2: / Study the need for the development of the criteria for the provision of warnings for rotor zones in terminal area

DEVELOPMENT OF CRITERIA FOR THE PROVISION OF WARNINGS FOR ROTOR ZONES IN THE TERMINAL AREA

(Presented by the Secretary)

SUMMARY
This study note invites the group to consider the development of criteria for the provision of warnings for rotor zones in the terminal area.

1.INTRODUCTION

1.1The group may wish to note that the Air Navigation Commission at its Thirteenth Meeting of the 132nd Session when reviewing the former ANC Task MET 9201 Operational requirements for the inclusion of severe mountain waves in SIGMET messages and wind shear warnings agreed to task the Secretariat with the assistance of the (former) WISTSG to study the need for the development of the criteria for the provision of warnings for rotor zones in terminal area.

1.2In this regard, as the group is aware,currently Annex 3 contains criteria related to the inclusion of mountain waves in SIGMET and AIRMET messages and special air reports(uplink).

1.3In addition the group may wish to note that the Secretariat, as a follow-up of the said task requested, through WISTSG-Memo/53 in 2005, to the WISTSG members their opinion regarding the need to develop such criteria for the provision of warnings. As a result of this consultation the Secretariat received only one reply from one WISTSG member as follows:

“We do not believe there is a pressing need in the UK for the development of criteria for the provision of warnings for rotor zones in the terminal area above and beyond the requirement that is already in place to issue SIGMET warnings of mountain wave activity and to include areas of likely mountain waves on low level significant weather charts (as mountain waves give rise to the generation of rotor zones). Again, this issue is going to be more of a problem for those airports whose terminal area lies in or very close to the lee of a large mountain ridge.”

1.3Considering the number of airports in the world that meet the conditions described in the last paragraph of the above reply which could merit the inclusion of rotor zones as a phenomena that prompt the issuance of aerodrome warnings and in light of the information provided the group may wish to discuss first the need for the issuance of such aerodrome warnings and second, if necessary to define appropriate criteria for their issuance. In this regardthe group may wish to agree that an issue of such scope requires time to do the work and is beyond the time frame of this meeting. In this regard the group may wish to agree to the following action:

Action agreed 1/..Need for the development of criteria for aerodrome warnings for rotor zones
That, an ad-hoc working group with participation of the members from (Rapporteur) and be tasked to:
a) evaluate the need for the issuance of aerodrome warnings for rotor zones in the terminal area;
b) if necessary, define appropriate criteria for the inclusion of the phenomena in aerodrome warnings; and
c) if necessary, prepare a draft proposal for its inclusion in Amendment 75 to Annex 3.

2.ACTION BY THE METWSG

2.1The METWSG is invited to:

a)note the information in this paper; and

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

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