For the purposes of this chapter, the following definitions are applicable:
AIRPORT: The Helena airport.
AIRPORT BOARD OF ADJUSTMENT: The board consisting of five (5) members appointed by the Helena city commission and Lewis and Clark County commissioners as provided in section 1-718 and 11-2707, Revised Codes of Montana, 1947.
AIRPORT ELEVATION: The established elevation of the highest point on the usable landing area.
AIRPORT HAZARD: Any structure, tree or use of land which obstructs the air space required for, or is otherwise hazardous to, the flight of aircraft in landing or taking off at the airport.
AIRPORT REFERENCE POINT: The point established as the approximate geographic center of the airport landing area and so designated.
HEIGHT: For the purpose of determining the height limitations in all zones established by this chapter and shown on the Helena airport zoning map, the datum shall be mean sea level elevation unless otherwise specified.
LANDING AREA: The area of the airport used for the landing, taking off, or taxiing of aircraft.
NONCONFORMING USE: Any preexisting structure, tree, natural growth or use of land which is inconsistent with the provisions of this chapter or amendment thereto.
NONPRECISION INSTRUMENT RUNWAY: A runway having or planned an instrument approach procedure utilizing area type navigation equipment for a straight in, nonprecision instrument approach.
PRECISION INSTRUMENT RUNWAY: A runway equipped or to be equipped with a precision electronic navigation aid or landing aid or other air navigation facilities, suitable to permit the landing of aircraft by an instrument approach under restricted visibility conditions.
RUNWAY: The paved surface of an airport landing strip.
STRUCTURE: An object or structure constructed or installed by man, including, but not limited to, buildings, towers, smoke stacks, and overhead transmission lines.
TREE: Any vegetation or other naturally growing object.
UTILITY RUNWAY: A runway that is constructed for and intended to be used by propeller driven aircraft of twelve thousand five hundred (12,500) pounds maximum gross weight or less. (Ord. 2359, 5-20-1985)