Fixed‐wing runways generally have several more imaginary surfaces than helicopter
landing areas do. For the type of helipads at SBAH, the following imaginary surfaces are
defined:
The primary surface immediately surrounds the landing surface offset by
150 feet and must be kept free of all obstructions not directly required for
airfield operations.
The approach‐departure clearance surface is symmetrically centered on the
extended helipad landing lane, beginning as an inclined plane at the end of the
primary surface and extending for 1,200 feet. The slope of the
approach‐departure clearance surface is 8:1. The width of this surface at the
primary surface is 300 feet, widening uniformly to a width of 600 feet at the end
point.
The transitional surface extends outward and upward at right angles to the
primary surface and extended landing lane at a slope of 2:1. The transitional
surface starts at the lateral edges of the primary surface and the
approach‐departure clearance surface. It continues outward and upward at the
prescribed slope to an elevation of 87.5 feet above the specified helipad. It then
rises vertically to an elevation of 150 feet above the helipad elevation.
The imaginary surfaces at SBAH extend approximately 140 feet past the northern and
114 feet past the western boundaries over undeveloped Arizona State Trust land that is
managed by the Arizona State Land Department, as well as roughly 1,160 feet to the
south over land that is part of Pinal Airpark. Figure 3‐12 depicts the imaginary surfaces
for helipads at SBAH.
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Arizona Army National Guard Profile