175.01 DEFINITIONS.
   As used in this chapter, unless the context otherwise requires:
      1.   “Airport” means the Denison Municipal Airport.
      2.   “Airport elevation” means the highest point of an airport’s usable landing area measured in feet above mean sea level, which elevation is established to be 1,276 feet.
      3.   “Hazard to air navigation” means an obstruction determined to have a substantial adverse effect on the safe and efficient utilization of the navigable air space.
      4.   “Airport primary surface” means a surface longitudinally centered on a runway. When the runway has a specially prepared hard surface, the primary surface of the runway will be that width prescribed in Part 77 of the Federal Aviation Regulations (FAR) for the most precise approach existing or planned for either end of that runway. The elevation of any point on the primary surface is the same as the elevation of the nearest point on the runway centerline.
      5.   “Airspace height” means for the purpose of determining the height limits in all zones set forth in this chapter and shown on the zoning map, the datum shall be mean sea level elevation unless otherwise specified.
      6.   “Control zone” means airspace extending upward from the surface of the earth which may include one or more airports and is normally a circular area of five (5) statute miles in radius, with extensions where necessary to include instrument approach and departure paths.
      7.   “Instrument runway” means a runway having an existing instrument approach procedure utilizing air navigation facilities or area type navigation equipment, for which an instrument approach procedure has been approved or planned.
      8.   “Minimum descent altitude” means the lowest altitude expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering in execution of a standard instrument approach procedure, where no electronic glide slope is provided.
      9.   “Minimum en route altitude” means the altitude in effect between radio fixes which assures acceptable navigational signal coverage and meets obstruction clearance requirements between those fixes.
      10.   “Minimum obstruction clearance altitude” means the specified altitude in effect between radio fixes on VOR airways, off-airways routes, or route segments which meets obstruction clearance requirements for the entire route segment and which assures acceptable navigational signal coverage only within twenty-two (22) miles of a VOR.
      11.   “Runway” means a defined area on an airport prepared for landing and takeoff of aircraft along its length.
      12.   “Visual runway” means a runway intended solely for the operation of aircraft using visual approach procedures with no straight-in instrument approach procedure and no instrument designation indicated on an FAA approved airport layout plan, military services approved military airport layout plan, or by any planning document submitted to the FAA by competent authority.