92 Ill. Adm. Code 16.70
Primary Surface
Section 16.70 Primary Surface
a) A
primary surface is longitudinally centered on a runway of each applicable
airport listed in Section 16.Appendix A. When the runway has a specially
prepared hard surface, the primary surface extends 200 feet beyond each end of
that runway. When the runway has no specially prepared hard surface or planned
hard surface, the primary surface ends at each end of that runway. The
elevation of any point on the primary surface is the same as the elevation of
the nearest point on the runway centerline. The width of a primary surface is:
1) 200
feet (Departmental standard);
2) 250 feet for utility
runways having only visual approaches;
3) 500 feet for utility
runways having non-precision instrument approaches;
4) For
other than utility runways, the width is:
A) 500 feet for visual
runways having only visual approaches;
B) 500
feet for non-precision instrument approach runways having existing or proposed visibility
minimums greater than three-fourths of a statute mile;
C) 1,000
feet for a non-precision instrument runway having a non-precision instrument
approach with visibility minimums as low as three-fourths of a statute mile,
and for precision instrument approach runways.
b) The
width of the primary surface of a runway will be the width prescribed in
subsection (a) of this Section for the most precise approach existing or
planned for either end of that runway.