Ala. Code § 41-10-96
The principal of and interest on the bonds shall be secured by a pledge of the rent, revenues and income out of which the bonds shall be made payable and by a pledge of any lease agreements covering the project or any part thereof from which the rent, revenues and income so pledged shall be derived and may be secured by an indenture covering such project. The trustee under an indenture may be a trust company or bank having trust powers, whether located within or without the state. The indenture may contain any agreements and provisions customarily contained in instruments securing evidences of indebtedness, including, without limiting the generality of the foregoing, provisions respecting the collection, segregation and application of the rent, revenues and income from any project covered by such indenture, the terms to be incorporated in the lease agreements respecting such project or any part thereof, the maintenance and insurance of such project, the creation and maintenance of special funds from the rent, revenues and income of such project and the rights and remedies available in the event of default to the holders of the bonds or the trustee under the indenture as the board shall deem advisable and as shall not be in conflict with the provisions of this article.
Ala. Code § 41-10-96 (1975)