IN Code § 8-21-10-8 (2021)
2021 Indiana Code|Title 8. Utilities and Transportation|Article 21. Aeronautics|Chapter 10. Regulation of Tall Structures|8-21-10-8. Airport and Heliport Imaginary Surfaces

Sec. 8. (a) The following airport imaginary surfaces are established with relation to any public-use airport and to each runway:(1) Horizontal surface: a horizontal plane one hundred fifty (150) feet above the established airport elevation, the perimeter of which is constructed by swinging arcs of specified radii from the center of each end of the primary surface of each runway of each airport and connecting the adjacent arcs by lines tangent to those arcs. The radii of each arc is five thousand (5,000) feet for all runways designated as utility or visual, and ten thousand (10,000) feet for all other runways.(2) Conical surface: a surface extending outward and upward from the periphery of the horizontal surface at a slope of twenty (20) to one (1) for a horizontal distance of four thousand (4,000) feet.(3) Primary surface: a surface longitudinally centered on a runway. When the runway has a specially prepared hard surface, the primary surface extends two hundred (200) feet beyond each end of the runway, but when the runway has no specially prepared hard surface, the primary surface ends at each end of that runway. The width of a primary surface is the following:(A) Two hundred fifty (250) feet for utility runways having only visual approaches.(B) Five hundred (500) feet for utility runways having nonprecision instrument approaches.(C) For other than utility runways, the width is the following:(i) Five hundred (500) feet for visual runways having only visual approaches.(ii) Five hundred (500) feet for nonprecision instrument runways having visibility minimums greater than three-fourths (3/4) of a statute mile.(iii) One thousand (1,000) feet for a nonprecision instrument runway, having a nonprecision instrument approach with visibility minimums as low as three-fourths (3/4) of a statute mile, and for precision instrument runways.(4) Approach surface: a surface longitudinally centered on the extended runway centerline and extending outward and upward from each end of the primary surface. An approach surface is applied to each end of each runway based upon the type of approach available or planned for that runway end. The following also applies to the approach surface:(A) The inner edge of the approach surface is the same width as the primary surface and it expands uniformly to a width of the following:(i) One thousand two hundred fifty (1,250) feet for that end of a utility runway with only visual approaches.(ii) One thousand five hundred (1,500) feet for that end of a runway other than a utility runway with only visual approaches.(iii) Two thousand (2,000) feet for that end of a utility runway with a nonprecision instrument approach.(iv) Three thousand five hundred (3,500) feet for that end of a nonprecision instrument runway other than utility, having visibility minimums greater than three-fourths (3/4) of a statute mile.(v) Four thousand (4,000) feet for that end of a nonprecision instrument runway, other than utility, having a nonprecision instrument approach with visibility minimums as low as three-fourths (3/4) of a statute mile.(vi) Sixteen thousand (16,000) feet for precision instrument runways.(B) The approach surface extends for a horizontal distance of the following:(i) Five thousand (5,000) feet at a slope of twenty (20) to one (1) for all utility and visual runways.(ii) Ten thousand (10,000) feet at a slope of thirty-four (34) to one (1) for all nonprecision instrument runways other than utility.(iii) Ten thousand (10,000) feet at a slope of fifty (50) to one (1) with an additional forty thousand (40,000) feet at a slope of forty (40) to one (1) for all precision instrument runways.(5) Transitional surfaces: these surfaces extend outward and upward at right angles to the runway centerline and the runway centerline extended at a slope of seven (7) to one (1) from the sides of the primary surface and from the sides of the approach surfaces. Transitional surfaces for those portions of the precision approach surface which project through and beyond the limits of the conical surface, extend a distance of five thousand (5,000) feet measured horizontally from the edge of the approach surface and at right angles to the runway centerline.(b) As used in subsection (a) in establishing airport imaginary surfaces:"Nonprecision instrument runway" means a runway having an existing instrument approach procedure utilizing air navigation facilities with only horizontal guidance, or area type navigation equipment, for which a straight-in nonprecision instrument approach procedure has been approved, or planned, and for which no precision approach facilities are planned, or indicated on a Federal Aviation Administration planning document."Precision instrument runway" means a runway having an existing instrument approach procedure utilizing an instrument landing system (ILS), microwave landing system (MLS), or a precision approach radar (PAR). It also means a runway for which a precision approach system is planned and is so indicated by a Federal Aviation Administration approved airport layout plan or other planning document."Utility runway" means 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."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 a Federal Aviation Administration approved airport layout plan or any other planning document.(c) The following heliport imaginary surfaces are established with relation to any public-use heliport:(1) Heliport primary surface: the area of the primary surface coincides in size and shape with the designated takeoff and landing area of a heliport. This surface is a horizontal plane at the elevation of the established heliport elevation.(2) Heliport approach surface: the approach surface begins at each end of the heliport primary surface with the same width as the primary surface, and extends outward and upward for a horizontal distance of four thousand (4,000) feet where its width is five hundred (500) feet. The slope of the approach surface is eight (8) to one (1) for civil heliports.(3) Heliport transitional surfaces: these surfaces extend outward and upward from the lateral boundaries of the heliport primary surface and from the approach surfaces at a slope of two (2) to one (1) for a distance of two hundred fifty (250) feet measured horizontally from the centerline of the primary and approach surfaces.As added by P.L.117-1983, SEC.1.