(A) The regulations prescribed by this chapter shall not be construed to require the removal, lowering, or other change or alteration of any structure or tree not conforming to the regulations as of April 1, 1967, 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 April 5, 1967, and which is diligently prosecuted.
(B) Notwithstanding the preceding provision of this section, the owner of any nonconforming structure or tree is required to permit the installation, operation, and maintenance thereon of such markers and lights as shall be deemed necessary by the Airport Zoning Officer 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 city.
(C) Whenever the Airport Zoning Officer determines that a nonconforming structure or tree has been abandoned or more than 50% torn down, physically deteriorated, or decayed, no such structure or tree shall be rebuilt or allowed to grow so as to exceed the applicable height limit or otherwise deviate from the zoning regulations.
('61 Code, § 10-5.301) (Ord. 106 C.S., passed 4-5-67)