The three main organs of ICAO are the assembly, the council, and the secretariat, headed by the Secretary General.
The all-member assembly meets every three years. Every member state has one vote in the assembly, and decisions are made by a simple majority vote unless otherwise specified by the Chicago Convention. Sessions have been held in many different cities.
The assembly makes policy recommendations, reviews the work of ICAO, offers guidance to other ICAO bodies, elects the council, and determines the budget. The assembly may amend the ICAO constitution by a two-thirds majority vote, and it has done so on several occasions. But amendments come into force for the states that ratify them only after they have been ratified by at least two-thirds of the ICAO member states as specified by the assembly. In other words, the assembly may feel that it would not be fair to introduce a particular innovation in international civil aviation unless certain states would abide by it. On the other hand, the assembly possesses a rather unusual prerogative to induce wide ratification of an amendment it has adopted: if a member state does not ratify a particular amendment within a given period of time, the assembly has the right to revoke that country's membership in ICAO. However, this provision (Article 94[b]) has never been invoked.
The council is a permanent body, composed of 33 member states elected by the assembly for three-year terms. In selecting the membership of the council, the assembly is required by the Chicago Convention to give adequate representation to nations of major importance in air transport, to nations that provide the largest share of facilities for international civil air navigation, and to nations whose inclusion on the council will ensure broad geographical representation.
Assad Kotaite of Lebanon, president of the council since 1976, was reelected in November 1998. He was elected by acclamation for a ninth consecutive term as council president.
The council's powers are unusually broad, as compared with those of the executive councils of most other specialized agencies. It adopts international standards and recommended practices regarding civil air navigation and transport. It may act as arbiter between member states on disputes relating to the interpretation or application of the Chicago Convention and its annexes. It may investigate any situation that presents avoidable obstacles to the development of international air navigation. In general, it may take whatever steps are necessary to maintain the safety and regularity of operation of international air transport.
The ICAO secretariat is headed by a Secretary General, who is appointed by the council. The Secretary General appoints the staff of the ICAO secretariat and supervises and directs its activities. In March 2000 the Council appointed Renato Cláudio Costa Pereira (of Brazil) as Secretary General for a second three-year term (beginning 1 August 2000).
ICAO headquarters are at 999 University Street, in the center of Montreal, occupying a 15-story tower with an adjoining complex offering complete conference facilities. ICAO maintains regional offices in Paris, Bangkok, Cairo, Mexico City, Nairobi, Lima, and Dakar to assist member states in providing aeronautical services.