CHAPTER IV MEASURES TO FACILITATE AIR NAVIGATION Article 22 Faclitationof Each contracting State agrees to adopt all practicable measures, through the issuance of special regulations or otherwise, to facilitate and expedite navigation by air- craft between the territories of contracting States, and to prevent unnecessary delays to aircraft, crews, passengers and cargo, especially in the administration of the laws relating to immigration, quarantine, customs and clear- ance. Article 23 custms and Each contracting State undertakes, so far as it may procdures find practicable, to establish customs and immigration procedures affecting international air navigation in ac- cordance with the practices which may be established or recommended from time to time, pursuant to this Con- vention. Nothing in this Convention shall be construed as preventing the establishment of customs-free airports. Article 24 Customs duty (a) Aircraft on a flight to, from, or across the territory of another contracting State shall be admitted tem- porarily free of duty, subject to the customs regulations of the State. Fuel, lubricating oils, spare parts, regular equipment and aircraft stores on board an aircraft of a contracting State, on arrival in the territory of another contracting State and retained on board on leaving the territory of that State shall be exempt from customs duty, inspection fees or similar national or local duties and charges. This exemption shall not apply to any quan- tities or articles unloaded, except in accordance with the customs regulations of the State, which may require that they shall be kept under customs supervision. (b) Spare parts and equipment imported into the ter- ritory of a contracting State for incorporation in or use on an aircraft of another contracting State engaged in inter- national air navigation shall be admitted free of customs duty, subject to compliance with the regulations of the State concerned, which may provide that the articles shall be kept under customs supervision and control. Article 25 Aircraft in distre Each contracting State undertakes to provide such measures of assistance to aircraft in distress in its terri- tory as it may find practicable, and to permit, subject to control by its own authorities, the owners of the aircraft TREATIES [61 STAT.
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