AMOSSG/5-SN No. 24

7/4/05

AERODROME METEOROLOGICAL OBSERVING SYSTEMS STUDY GROUP (AMOSSG)

FIFTH MEETING

Montreal, 11 to 14 April 2005

Agenda Item	5:	Aerodrome observation requirements
5.1:	Reporting requirements and criteria

THE ASSESSMENT AND REPORT OF RUNWAY VISUAL RANGE

(Presented by Akoa Benoit Okossi)

SUMMARY
This paper outlines the requirements to specify the assessed RVR to report when RVR lies between 1500 meters and 2000 meters and suggests to develop a draft amendment to clarify these uncertainties.

1.	INTRODUCTION

1.1	The summary of AMOSSG/4 conclusions states that RVR in WMO N 306, Manual on Codes is not consistent with ICAO Annex 3. So, the group agreed that WMO should be invited to align WMO N 306, as appropriate.

2.	DISCUSSION

2.1	The paragraph 4.6.3.3, Chapter 4 of ICAO Annex 3 related to the RVR reporting, specifies that Runway Visual Range assessed according to 4.6.3.1 and 4.6.3.2 will be reported in meters throughout periods when either the visibility or the runway visual range is observed to be less than 1500 meters.

2.2	According to 4.3.6.2 of Appendix 3 of ICAO Annex 3, fifty meters should be considered lower limit and 2000 meters the upper limit for assessment of runway visual range. Outside of these limits, the MET REPORT and SPECIAL reports and METAR and SPECI reports should only indicate that the RVR is less than 50 meters or more than 2000 meters.

2.3	From what said above, it is noted that there is no indication about what to do when the assessed RVR lies between 1500 meters and 2000 meters.

3.	CONCLUSION

3.1	ICAO Annex 3 does not specify the RVR values to be reported when these values are assessed to lie between 1500 and 2000 meters. The group may wish to draft an amendment to Annex 3 to specify these values.

4.	ACTION BY THE GROUP

4.1	The group is invited to:

a)	note information included in this paper, and

b)	recommend that an amendment to Annex 3 be developed with the assistance of the AMOSSG to clarify the reporting of RVR, specially within 1500 meters and 2000 meters.

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