---
kind: "section"
citation: "14 C.F.R. § 77.23"
title: "14"
number: "77.23"
heading: "Heliport imaginary surfaces."
url: "https://uscodex.org/cfr/14/77.23"
---

# §77.23. Heliport imaginary surfaces.

- (a) **Primary surface.** The area of the primary surface coincides in size and shape with the designated take-off and landing area. This surface is a horizontal plane at the elevation of the established heliport elevation.
- (b) **Approach surface.** The approach surface begins at each end of the heliport primary surface with the same width as the primary surface, and extends outward and upward for a horizontal distance of 4,000 feet where its width is 500 feet. The slope of the approach surface is 8 to 1 for civil heliports and 10 to 1 for military heliports.
- (c) **Transitional surfaces.** These surfaces extend outward and upward from the lateral boundaries of the primary surface and from the approach surfaces at a slope of 2 to 1 for a distance of 250 feet measured horizontally from the centerline of the primary and approach surfaces.

## Notes

### Authority

Authority: 49 U.S.C. 106 (g), 40103, 40113-40114, 44502, 44701, 44718, 46101-46102, 46104.

### Source

Source: Docket FAA-2006-25002, 75 FR 42303, July 21, 2010, unless otherwise noted.