scope:

INTRODUCTION

This manual was first issued as a circular in 1973 (Circular 113, Runway Visual Range Observing and Reporting Practices). It was based on information provided by a number of States on their runway visual range (RVR) assessment practices. Owing to numerous subsequent changes to the provisions governing RVR contained in Annex 3 - Meteorological Service for International Air Navigation and to changes in RVR assessment practices by States, it became necessary to produce a revised edition of the material in the circular. In 1981, in view of the expected wider operational use of the document, it was issued as a manual and contained updated information on assessment practices, which had been made available by a number of States, together with information on technical developments and research.

As a result of subsequent amendments to Annex 3 provisions related to RVR assessment, it became clear by 1995 that the manual needed to be revised. In particular, detailed guidance concerning forward-scatter meters was considered necessary following comparisons between transmissometers and forward-scatter meters conducted by a number of States which had indicated that forward-scatter meters were capable of producing comparable output to transmissometers. Further amendments to Annex 3 including the introduction of a provision to use the maximum light intensity for the assessment of RVR resulted in the publication of the third edition of the manual in 2005.

The purpose of this manual is to assist States in setting up efficient RVR systems, or, where such systems already exist, in updating and standardizing them. This is particularly important in view of the different assessment practices being used. It is hoped that the manual will also stimulate further research and development in the field of RVR assessment.

In conclusion, it should be stressed that nothing in the manual should be taken as contradicting or conflicting with the RVR provisions contained in Annex 3, Chapter 4, 4.6.3, and Appendix 3, 4.3.

Note.- RVR is the approved ICAO abbreviation for runway visual range and is normally used in this manual instead of the full name. See the Procedures for Air Navigation Services - ICAO Abbreviations and Codes (PANS-ABC, Doc 8400).