Before any non-conforming structure or tree may be replaced, substantially altered or repaired, rebuilt, allowed to grow higher or replanted a permit shall be secured from the Planning Commission. No permit shall be granted that would allow the establishment or creation of an airport hazard or permit a non-conforming structure or tree or non-conforming use to be made or become higher or become a greater hazard to air navigation than it was on December 17, 1962, or than it is when the application for a permit is made. Except as provided in this chapter, all applications for permits shall be granted. No permit shall be required to make maintenance repairs to or to replace parts of existing structures which do not enlarge or increase the height of the existing structure.
(1966 Code, § 3-9) (Ord. 231, § 9)