The current 2010 Town of Marana General Plan identifies the area around the Pinal
Airpark and SBAH as airport land use, however there are no specific provisions regarding
AZARNG operations at the Heliport. The existing General Plan does show a planned
growth corridor from the Town to the northwest where Pinal Airpark and SBAH are
located.
The FAA and DOD have identified certain imaginary surfaces around runways and
helipads that are used to determine how structures and facilities are evaluated to identify
if they pose a vertical obstruction in relation to the airspace around a runway or helipad.
The levels of imaginary surfaces build upon one another and are designed to eliminate
obstructions to air navigation and operations, either natural or man‐made. The
dimension or size of an imaginary surface depends on the type of runway or helipad
around which it is based.
The following provides a description of imaginary surfaces dimensions and layouts as
defined by DoD Unified Facilities Criteria 3‐260‐01 Airfield and Heliport Planning and
Design. An illustration of example helipad imaginary surfaces can be found on
Figure 3‐11 in Chapter 3 of this Background Report
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 centerline
of the helipad and starting, 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 150 feet, widening uniformly to a width of 500 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 established helipad. It
then rises vertically to an elevation of 150 feet above the established helipad
elevation.
Figure 3‐12 in Chapter 3 of this Background Report illustrates the imaginary surfaces for
the helipads at SBAH. To the west and north, the portions that go outside SBAH’s
boundary are over undeveloped Arizona State Trust Land. to the south, they go over land
within Pinal Airpark, include the northern end of the runway. Any future development in
these areas should consider the height limits associated with the respective imaginary
surfaces.
5-84
Compatibility Assessment