---
title: "CS HPT-DSN.E.400 – CS HPT-DSN.E.430: CHAPTER E — OBSTACLE LIMITATION SURFACES AND REQUIREMENTS (Certification Specifications and Guidance Material for Heliport Design (CS-HPT-DSN) — Issue 1, Aerodromes) — rule index · Avioverse"
description: "CS HPT-DSN.E.400 – CS HPT-DSN.E.430, Regulation (EU) No 139/2014. CS HPT-DSN.E.400 Applicability The purpose of the obstacle limitation surfaces is to…"
url: "https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and"
---

# CHAPTER E — OBSTACLE LIMITATION SURFACES AND REQUIREMENTS

Certification Specifications and Guidance Material for Heliport Design (CS-HPT-DSN) — Issue 1 · Aerodromes · Regulation (EU) No 139/2014 · CS HPT-DSN.E.400 – CS HPT-DSN.E.430

On this page

1. ## [CS HPT-DSN.E.400 Applicability](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/cs-hpt-dsn-e-400)

   The purpose of the obstacle limitation surfaces is to define the airspace around heliports so as to permit intended helicopter operations to be conducted…

2. ## [GM1 HPT-DSN.E.400 Applicability](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/gm1-hpt-dsn-e-400)

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3. ## [CS HPT-DSN.E.410 Approach surface](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/cs-hpt-dsn-e-410)

   Applicability: The purpose of an approach surface is to protect a helicopter during the final approach to the FATO by defining an area that should be…

4. ## [GM1 HPT-DSN.E.410 Approach surface](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/gm1-hpt-dsn-e-410)

   Consultations with helicopter operators could assist the aerodrome operator in determining the appropriate slope category to apply according to the…

5. ## [CS HPT-DSN.E.420 Take-off climb surface](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/cs-hpt-dsn-e-420)

   Applicability: The purpose of the take-off climb surface is to protect a helicopter on take-off and during climb-out.

6. ## [GM1 HPT-DSN.E.420 Take-off climb surface](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/gm1-hpt-dsn-e-420)

   Helicopter take-off performance is reduced in a curve, so a straight portion along the take-off climb surface prior to the start of the curve allows for…

7. ## [CS HPT-DSN.E.430 Obstacle limitation requirements](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/cs-hpt-dsn-e-430)

   General: The following obstacle limitation surfaces should be established for a FATO:

8. ## [GM1 HPT-DSN.E.430 Obstacle limitation requirements](https://avioverse.aero/regulations/easa/aerodromes/cs-hpt-dsn/chapter-e-obstacle-limitation-surfaces-and/gm1-hpt-dsn-e-430)

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Consolidated from the EASA Easy Access Rules (revision 13 Mar 2026, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.

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