---
title: "GM1 ADR-DSN.H.430 Transitional surface — Certification Specifications and Guidance Material for Aerodrome Design (CS-ADR-DSN) — Issue 7, Aerodromes · Avioverse"
description: "When the elevation of a point on the lower edge is along the strip and equal to the elevation of the nearest point on the centre line of the runway or…"
url: "https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-h-obstacle-limitation-surfaces/gm1-adr-dsn-h-430"
---

# GM1 ADR-DSN.H.430 Transitional surface

Certification Specifications and Guidance Material for Aerodrome Design (CS-ADR-DSN) — Issue 7 · Regulation (EU) No 139/2014 · EAR revision 13 Mar 2026

GM Guidance material

## GM1 ADR-DSN.H.430 Transitional surface

When the elevation of a point on the lower edge is along the strip and equal to the elevation of the nearest point on the centre line of the [runway](https://avioverse.aero/glossary/easa/runway) or its extension as a result the transitional surface along the strip should be curved if the runway profile is curved, or a plane if the runway profile is a straight line. The intersection of the transitional surface with the inner horizontal surface should also be a curved or a straight line depending on the runway profile.

GM · GM1 ADR-DSN.H.430 — Regulation (EU) No 139/2014 · ED Decision 2014/013/R · Aerodromes Easy Access Rules · EAR revision 13 Mar 2026

[All rules in CHAPTER H — OBSTACLE LIMITATION SURFACES](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-h-obstacle-limitation-surfaces)

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.