92 Ill. Adm. Code 14.830
Obstructions
Section 14.830 Obstructions
Minimum heliport obstruction clearance standards shall be in
accordance with Section 14.Appendix G, Illustration D. In order to be eligible
for a Certificate of Approval under this Part, a heliport must initially and
continually be free of obstructions (e.g., power poles, trees, fencing, etc.)
on all approach/takeoff paths within the glide ratio and height limitations
shown in Section 14.Appendix G, Illustration D.