Section 16.90  Transitional Surfaces

a)         Transitional surfaces extend outward and upward in a direction perpendicular to the runway centerline and to an extension of that line at a slope of seven feet horizontally for each foot vertically (7:1) beginning at the sides (cf., ends) of the primary and approach surfaces extending to the horizontal and the conical surface.  When the approach slope extends beyond the lateral limits of the conical surface, the transitional surface extends for 5,000 feet horizontally.  The beginning elevation of these surfaces is the same elevation as the primary and approach surfaces.

b)         Airports covered by Departmental standards only have transitional surfaces that begin at the sides (cf., ends) of the primary surface extending to the horizontal surface (i.e., no transition surfaces that extend off the approach surfaces).