Section 70 ILCS 15/16 - Use of income and revenues received(a) Whenever revenue bonds are issued and outstanding under Sections 14 and 15, all of the income and revenues received from the operation of the airport or airports, related facility or facilities, perimeter area or areas and perimeter area facility or facilities pledged to secure the payment of the interest and principal of such bonds shall be paid to the State Treasurer and deposited in a separate fund, to be designated the Kankakee River Valley Area Airport Authority Bond Retirement and Interest Fund, of which the State Treasurer shall be ex officio custodian and which shall be used only in paying the principal and interest of these revenue bonds and reserves therefor and the cost of rental, maintenance, operation and depreciation of such airport or airports, related facility or facilities, perimeter area or areas and perimeter area facility or facilities to such extent and in such order of priority as shall be provided by the respective resolutions authorizing revenue bonds. No priority accorded by such a resolution may be impaired by a subsequent resolution authorizing revenue bonds unless specifically so permitted by a covenant of the kind authorized to be included in a resolution by Section 15.(b) The Fund shall be held, invested and disbursed for the purposes provided in this Section, upon the order of the Authority and in accordance with provisions and covenants of any bond resolution authorizing the issuance of bonds. The interest accruing on the Fund shall be computed and added to the principal thereof every 6 months.(c) In addition to the special audits prescribed by this Act, the Fund shall also be subject to audit in the same manner as provided for the audit of State funds and accounts.(d) The Fund shall be protected by a corporate surety bond, executed by the Treasurer, with a surety authorized to do business under the laws of the State of Illinois, in an amount to be fixed by resolution of the Authority and approved by the Governor, which amount may be increased or diminished at any time. The premiums on that bond are payable from the funds of the Authority. The bond shall be subject to the approval of the Governor and Attorney General of the State of Illinois, and, when so approved, shall be filed in the office of the Secretary of State.(e) The Fund shall be considered always appropriated for the purposes of disbursements as provided in this Act, and shall be paid out and disbursed only as provided in this Act and may not, at any time, be appropriated or diverted to any other use or purpose.(f) Such income and revenues in excess of requirements for payment of principal of and interest upon these bonds and reserves therefor and for payment of cost of maintenance, operation and depreciation of the airport or airports, related facility or facilities, perimeter area or areas and perimeter area facility or facilities may be used for rehabilitation, reconstruction and expansion of existing airports, related facilities, perimeter areas and perimeter area facilities, or for retirement of any outstanding bonds issued for airport purposes. After all such bonds have been paid, such income and revenues may be transferred to the general corporate fund of the Authority and be used for the maintenance, operation, repair and development of such airport or airports, related facility or facilities, perimeter area or areas, and perimeter area facility or facilities, or for any corporate purpose.