PURPOSE

This circular aims to provide an overarching conceptual understanding of the surface friction characteristics that contribute to controlling an aircraft via the critical tire-to-ground contact area. The intent is to provide broad and fundamental concepts to support proposed amendments, by the ICAO Friction Task Force, to the Standards and Recommended Practices (SARPs) in Annex 14 — Aerodromes, Volume I — Aerodrome Design and Operations and Annex 15 — Aeronautical Information Services.

The proposed amendments address the following issues:

a) surface friction characteristics of pavements and runway surface contaminants;

b) how surface characteristics relate to aircraft performance;

c) assessment of runway surface conditions;

d) reporting and dissemination of runway surface conditions; and

e) the need for appropriate training of personnel involved in c) and d).