92 Ill. Adm. Code 16.80
Approach Surface
Section 16.80 Approach Surface
An approach surface is longitudinally centered on the
extended runway centerline and extends outward and upward from each end of the
primary surface. An approach surface is applied to each end and is based upon
the type of approach available or planned for that runway end.
a) The
inner edge of the approach surface is the same width as the primary surface and
it expands uniformly to a width of:
1) 800 feet (Departmental
standard);
2) 1,250 feet for that end
of a utility runway with only visual approaches;
3) 1,500
feet for that end of a runway other than a utility runway with only visual
approaches;
4) 2,000
feet for that end of a utility runway with a non-precision instrument approach;
5) 3,500
feet for that end of a non-precision instrument runway, other than utility,
having visibility minimums greater than three-fourths of a statute mile;
6) 4,000
feet for that end of a non-precision instrument runway, other than utility,
having a non-precision instrument approach with visibility minimums as low as
three-fourths of a statute mile; and
7) 16,000 feet for
precision instrument approach runways.
b) The approach surface
extends for a horizontal distance of:
1) 3,000
feet at a slope of 20 feet horizontally for each foot vertically (Departmental
standard);
2) 5,000
feet at a slope of 20 feet horizontally for each foot vertically for all utility
and visual runways;
3) 10,000
feet at a slope of 34 feet horizontally for each foot vertically for all
non-precision instrument approach runways other than utility; and
4) 10,000
feet at a slope of 50 feet horizontally for each foot vertically with an
additional 40,000 feet at a slope of 40 feet horizontally for each foot
vertically for all precision instrument approach runways.
c) The
outer width of an approach surface to an end of a runway will be that width
prescribed in this Section 16.80 for the most precise approach, existing or
planned, for that runway end.