Tcas

ACAS II Guide
Airborne Collision Avoidance System II (incorporating version 7.1)
January 2012

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ACAS II GUIDE January 2012

NOTE
This Guide has been designed to support the training of people involved in the use of the Airborne Collision Avoidance System (ACAS). However, it is not, per se, designed for the complete training of controllers or pilots. Theprincipal and essential technical and operational features of ACAS II are introduced. For a deeper knowledge, the reader is advised to refer to documentation listed in the bibliography section. This Guide describes the ACAS II concept and technical details as well as operation principles of TCAS II versions 7.0 and 7.1. TCAS II version 6.04a and TCAS I are not covered because they are outside thescope. The information contained in this Guide, EUROCONTROL ACAS II Bulletins and training presentations is based on the ICAO provisions and other applicable regulations. The information is considered to be accurate at the time of publishing but is subject to change

For further information please contact: acas@eurocontrol.int www.eurocontrol.int/acas

COPYRIGHT AND DISCLAIMER NOTICE©2012 The European Organisation for the Safety of Air Navigation (EUROCONTROL). This document is published by EUROCONTROL for information purposes. It may be copied in whole or in part provided that EUROCONTROL is mentioned as a source and to the extent justified by the non-commercial use (not for sale). The information in this document may not be modified without prior written permission fromEUROCONTROL. The use of this document is at user's sole risk and responsibility. EUROCONTROL expressly disclaims any and all warranties with respect to the document, expressed or implied. Additionally, the disclaimer available under www.eurocontrol.int/acas applies to the information contained in this Guide.

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ACKNOWLEDGMENTS
This ACASII Guide has been developed by EUROCONTROL with the help of QinetiQ and the German Airline Pilots’ Association (Vereinigung Cockpit). The Guide is partially based on the ACAS II Brochure that was originally developed for the EUROCONTROL ACASA project (ACAS Analysis) in 2000. CENA (Centre d’Etudes de la Navigation Aérienne) and EUROCONTROL have contributed to the development of the Brochure.Some sections of this Guide are based on the information contained in the FAA-published TCAS II version 7.1 brochure.

HISTORY OF CHANGES EDITION NUMBER 1.0 PAGES AFFECTED All

EDITION DATE 12 January 2012

REASON FOR CHANGE First edition.

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Table of Contents
PREFACE.........................................................................................................................................................8 INTRODUCTION.............................................................................................................................................9 Historical background................................................................................................................................ 9 ACAS and TCAS .......................................................................................................................................... 10 ACAS principles.......................................................................................................................................... 10 ACASstandards.......................................................................................................................................... 10 Early versions of TCAS II (versions 6.02 and 6.04A) ............................................................................ 11 TCAS II version 7.0 ..................................................................................................................................... 11 TCAS II version 7.1...