CS ADR-DSN.H.420 Inner horizontal surface

(a)Applicability: The purpose of the inner horizontal surface is to protect airspace for visual manoeuvring prior to landing.

(b)Description: A surface located in a horizontal plane above an aerodrome and its environs.

(c)Characteristics: The outer limits of the inner horizontal surface are defined by a circle centred on the geometric centre of the runway, by a convex contour composed of circular arcs centred on the intersections of the extended RWY centre line with the end of the RWY strip, joined tangentially by straight lines parallel to the runway centre line, as shown in Figure H-1, or on other points established for such purpose.

(d)The height of the inner horizontal surface should be measured above an established elevation datum. The elevation datum used for the height of the inner horizontal surface should be:

(1)the elevation of the highest point of the lowest threshold of the related runway; or

(2)the elevation of the highest point of the highest threshold of the related runway; or

(3)the elevation of the highest point of the runway; or

(4)the aerodrome elevation.

[Issue: ADR-DSN/3]