A. Regulations Not Retroactive: These regulations shall not be construed to require the removal, lowering or other changes or alteration of any structure or tree not conforming to the regulations as of the effective date hereof, or otherwise interfere with the continuance of any nonconforming use. Nothing herein contained shall require any change in the construction, alteration or intended use of any structure, the construction or alteration of which was begun prior to the effective date of these regulations and is diligently prosecuted.
B. Marking And Lighting: Notwithstanding the preceding provision of this section, the owner of any nonconforming structure or tree is hereby required to permit the installation, operation and maintenance thereon of such markers and lights as shall be deemed necessary by the city council to indicate to the operators of aircraft in the vicinity of the airport the presence of such airport hazards. Such markers and lights shall be installed, operated and maintained at the expense of the owner of the nonconforming structure or tree, and shall conform to the then current federal aviation administration rules and regulations. (Ord. 912, 10-9-1995)