The office of Superintendent shall be deemed vacant at the end of the incumbent's six year term or in case of his death, removal from office as herein provided or his resignation. If within 90 days after the organization of the Commission, or a vacancy occurs in such office, the county board fails to appoint from the number found eligible, a Superintendent, the Commission shall appoint one of such eligible candidates to be County Superintendent of Airports.
620 ILCS 50/43