(a) Except as otherwise provided in (b) of this section, if the law of this state governs perfection of a security interest or agricultural lien, the office in which to file a financing statement to perfect the security interest or agricultural lien is
(1) the office designated for the recording of a mortgage on the related real property if
(A) the collateral is as-extracted collateral or timber to be cut; or
(B) the financing statement is filed for record as a fixture filing and the collateral is goods that are or are to become fixtures; or
(2) in all other cases, the central filing office of the Department of Natural Resources established under AS 44.37.027, including a case in which the collateral consists of goods that are or are to become fixtures and the financing statement is not filed for record as a fixture filing.
(b) The office in which to file a financing statement to perfect a security interest in collateral, including fixtures, of a transmitting utility is the central filing office of the Department of Natural Resources established under AS 44.37.027. The financing statement also constitutes a fixture filing as to the collateral indicated in the financing statement that is or is to become fixtures.