Article 4
1. The request for escorted or unescorted transit by air and the associated assistance measures under Article 5(1) shall be made in writing by the requesting Member State. It shall reach the requested Member State as early as possible, and in any case no later than two days before the transit. This time limit may be waived in particularly urgent and duly justified cases. 2. The requested Member State shall inform the requesting Member State forthwith of its decision within two days. This time limit may be extended in duly justified cases by a maximum of 48 hours. Transit by air shall not be started without the approval of the requested Member State. Where no reply is provided by the requested Member State within the deadline referred to in the first subparagraph, the transit operations may be started by means of a notification by the requesting Member State. Member States may provide on the basis of bilateral or multilateral agreements or arrangements that the transit operations may be started by means of a notification by the requesting Member State. Member States shall notify the Commission regarding the agreements or arrangements referred to in the third subparagraph. The Commission shall regularly report to the Council on such agreements and arrangements. 3. For the purposes of dealing with the request under paragraph 1, the information on the form to be used for requesting and authorising transit by air in accordance with the Annex shall be forwarded to the requested Member State. The measures necessary for the update and the adjustment of the transit request as set out in the Annex as well as the methods of its transmission shall be taken in accordance with the procedure referred to in Article 9(2). 4. With respect to any request for transit, the requesting Member State shall provide the requested Member State with the details as provided for in the Annex. 5. The Member States shall each appoint a central authority to which requests under paragraph 1 are to be sent. The central authorities shall appoint contact points for all the relevant airports of transit who can be contacted throughout the transit operations.