Maryland Code, Transportation § 5-505

(1) Substantially alter any nonconforming structure or use; or

(2) Undertake or allow any activity prohibited by § 5-504(a) of this subtitle.

(b)(1) Before any work that requires a permit under this section is started on an operation or project and before any growth that requires a permit under this section is allowed of a tree or other vegetation, the owner of the land or structure shall obtain a permit from the Administration.

(2) The application for a permit shall be accompanied by the plats, drawings, and other information necessary to enable the Administration to determine if the proposed operation or project will comply with every applicable airport zoning regulation.

(c)(1) Except as otherwise provided in paragraph (3) of this subsection, the Administration may not issue a permit unless every airport zoning regulation applicable to the airport zoning district in which the land or structure is located will be complied with fully.

(2) The Administration shall issue a permit as a matter of right for the replacement or alteration of a nonconforming use or structure, except that the Administration may not issue any permit that will allow a structure or tree or other vegetation to be higher than or to be a greater hazard to air navigation than it was when the applicable airport zoning regulation was adopted.

(3) The Administration may issue a permit to any person acting on behalf of the Administration or any federal agency on land owned by the State or the federal government if the proposed activity complies with all applicable federal aviation regulations.

(1) The Administration shall notify the applicant in writing of its reasons for the disapproval; and

(2) If the Board of Airport Zoning Appeals is authorized to grant a variance from the applicable regulation, the applicant may appeal to the Board as provided in § 5-507 of this subtitle.