Article 85 Chicago Convention

Arbitration procedure

If any contracting State party to a dispute in which the decision of the Council is under appeal has not accepted the Statute of the Permanent Court of International Justice and the contracting States parties to the dispute cannot agree on the choice of the arbitral tribunal, each of the contracting States parties to the dispute shall name a single arbitrator who shall name an umpire. If either
contracting State party to the dispute fails to name an arbitrator within a period of three months from the date of the appeal, an arbitrator shall be named on behalf of that State by the President of the Council from a list of qualified and
available persons maintained by the Council. If, within thirty days, the arbitrators cannot agree on an umpire, the President of the Council shall designate an umpire from the list previously referred to. The arbitrators and the umpire shall then jointly constitute an arbitral tribunal. Any arbitral tribunal established under this or the preceding Article shall settle its own procedure and give its decisions by majority vote, provided that the Council may determine procedural questions in the event of any delay which in the opinion of the Council is excessive.

See also: Article 84 Chicago Convention