If within 15 days after such notice has been sent, an arbitrator has not been appointed by a party, the AAA shall make the appointment.

R-13. Appointment of Chairperson by Party-Appointed Arbitrators or Parties

(a) If, pursuant to Section R-12, either the parties have directly appointed arbitrators, or the arbitrators have been appointed by the AAA, and the parties have authorized them to appoint a chairperson within a specified time and no appointment is made within that time or any agreed extension, the AAA may appoint the chairperson.

(b) If no period of time is specified for appointment of the chairperson and the party-appointed arbitrators or the parties do not make the appointment within 15 days from the date of the appointment of the last party-appointed arbitrator, the AAA may appoint the chairperson.

(c) If the parties have agreed that their party-appointed arbitrators shall appoint the chairperson from the National Roster, the AAA shall furnish to the party-appointed arbitrators, in the manner provided in Section R-11, a list selected from the National Roster, and the appointment of the chairperson shall be made as provided in that Section.