ICAO Doc 9931:2010

The purpose of this manual is to provide guidance on continuous descent operations (CDO) and to harmonize its development and implementation. To achieve this, airspace design, instrument flight procedure design and air traffic control (ATC) techniques should all be employed in a cohesive manner. This will then facilitate the ability of flight crews to use in-flight techniques to reduce the overall environmental footprint and increase the efficiency of aircraft operations.