13. Amendments proposed to the Technical Regulations — as a rule — are approved by Congress. 14. If a recommendation for an amendment is made by a session of the appropriate technical commission and if the new regulation needs to be implemented before the time of next Congress, the Executive Council may, on behalf of the Organization, approve the amendment in accordance with Article 14(c) of the Convention. Amendments to annexes to the Technical Regulations proposed by the appropriate technical commissions are normally approved by the Executive Council. 15. If a recommendation for an amendment is made by the appropriate technical commission and the implementation of the new regulation is urgent, the President of the Organization may, on behalf of the Executive Council, take action as provided by General Regulation 9(5). 16. As far as the publication of updated material in WMONo. 49 is concerned, new editions of Volumes I and III are normally issued after each session of Congress (i.e. fouryearly). The material in Volume II is prepared by the World Meteorological Organization and the International Civil Aviation Organization working in close cooperation, in accordance with the Working Arrangements agreed by these Organizations; this also applies to the issuing of new editions of Volume II. In the period between the publication of two subsequent editions, the Technical Regulations are kept up to date by means of supplements, as necessary. 17. As decided by Resolution 1 (Cg-X), the amendments to the Technical Regulations adopted by Tenth Congress and incorporated in the 1988 edition of Volumes I and III and into the p