Legal functions

The Bureau provides advice and assistance to the Secretary General and through him to Council and other  bodies of the Organization and to ICAO Member States on constitutional, administrative and procedural matters, on problems of international law, air law, commercial law, labour law and related matters.  The Bureau also conducts research and studies in the field of private and public international air law, prepares documentation for, and serves as the Secretariat of  the Legal Committee: relevant bodies of the Assembly; and Diplomatic Conferences which adopt multilateral treaties on international air law.

 
The Bureau is responsible for the depositary functions of ICAO under several treaties, as well as the registration of agreements or arrangements pursuant to Articles 81 and 83 of the Chicago Convention.
 
The functions of the Legal Bureau also include cooperation and coordination in legal activities with the United Nations and other international organizations, including the implementation of ICAO’s Policy on Regional Cooperation involving Regional Organizations and regional civil aviation bodies.

External Relations functions

The Bureau is responsible for reviewing, advising on and coordinating ICAO's relations with member and non-member States, the Organizations of the United Nations Common System and with other international organizations.
 
The Bureau monitors activities of the international system which are of mutual interest to ICAO, the United Nations and other international organizations, directs attention to international affairs and political developments which may affect ICAO, and makes arrangements for the representation of the Organization at meetings of other organizations.
 
The Bureau also provides policy guidance and advice on matters relating to the privileges and immunities granted to the Organization, national representatives and staff of the Secretariat. It acts as the focal point for ICAO's relations with the Host States of the Organization's Headquarters and of the Regional Offices, and is responsible for arranging and supervising the ICAO Familiarization Course.