Page 238 - Planning and Design of Airports

Geometric Design of the Airfield 203

area. The runway safety area includes the structural pave-
ment, shoulders, blast pad, and stopway, if provided. This
area should be capable of supporting emergency and mainte-
nance equipment as well as providing support for aircraft.
The runway safety area is cleared, drained, and graded and
should have no potentially hazardous ruts, humps, depres-
sions, or other surface variations. It should be free of objects
except for objects that are required to be located in the run-
way safety area because of their function. These objects are
required to be constructed on frangible mounted structures at
the lowest possible height with the frangible point no higher
than 3 in above grade.
5. The runway object-free area (OFA) is defined by the FAA as a
two-dimensional ground area surrounding the runway which
must be clear of parked aircraft and objects other than those
whose location is fixed by function.
6. The runway obstacle-free zone (OFZ) is a defined volume of
airspace centered above the runway which supports the tran-
sition between ground and airborne operations. The FAA spec-
ifies this as the airspace above a surface whose elevation is
the same as that of the nearest point on the runway centerline
and extending 200 ft beyond each end of the runway.
7. The inner approach obstacle-free zone, which applies only to
runways with approach lighting systems, is the airspace
above a surface centered on the extended runway centerline
beginning 200 ft beyond the runway threshold at the same
elevation as the runway threshold and extending 200 ft beyond
the last light unit on the approach lighting system. Its width
is the same as the runway obstacle-free zone and it slopes
upward at the rate of 50 horizontal to 1 vertical.
8. The inner transitional obstacle-free zone, which applies only to pre-
cision instrument runways, is defined by the FAA as the volume
of airspace along the sides of the runway and the inner approach
obstacle-free zone. The surface slopes at the rate of 3 horizontal
to 1 vertical out from the edge of the runway obstacle-free zone
and the inner approach obstacle-free zone until it reaches a height
of 150 ft above the established airport elevation.
9. The runway protection zone (RPZ) is an area on the ground
used to enhance the protection of people and objects near the
runway approach.

The FAA runway standards related to the pavement and shoulder
width, the safety area, the blast pad, and the obstacle-free surfaces are
given in Tables 6-7 and 6-8. Similar data for the ICAO are given in
Table 6-9.