---
title: "CS ADR-DSN.L.525 Runway designation marking — Certification Specifications and Guidance Material for Aerodrome Design (CS-ADR-DSN) — Issue 7, Aerodromes · Avioverse"
description: "Applicability: A runway designation marking should be provided at the thresholds of a runway."
url: "https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-l-visual-aids-for-navigation-markings/cs-adr-dsn-l-525"
---

# CS ADR-DSN.L.525 Runway designation marking

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

IR Implementing rule

## CS ADR-DSN.L.525 Runway designation marking

(a) Applicability: A [runway](https://avioverse.aero/glossary/easa/runway) designation [marking](https://avioverse.aero/glossary/easa/marking) should be provided at the thresholds of a runway.

(b) Location and positioning: A runway designation marking should be located at a [threshold](https://avioverse.aero/glossary/easa/threshold) as shown in Figure L-1 as appropriate.

(c) Characteristics:

(1) A runway designation marking should consist of a two-digit number and on parallel runways should be supplemented with a letter.

(i) On a single runway, dual parallel runways and triple parallel runways, the two-digit number should be the whole number nearest the one-tenth of the magnetic North when viewed from the direction of approach.

(ii) On four or more parallel runways, one set of adjacent runways should be numbered to the nearest one-tenth magnetic azimuth and the other set of adjacent runways numbered to the next nearest one-tenth of the magnetic azimuth.

(iii) When a runway designation marking consists of a single digit number, it should be preceded by a zero.

(2) In the case of parallel runways, each runway designation number should be supplemented by a letter as follows, in the order shown from left to right when viewed from the direction of approach:

(i) for two parallel runways: ‘L’ ‘R’;

(ii) for three parallel runways: ‘L’ ‘C’ ‘R’;

(iii) for four parallel runways: ‘L’ ‘R’ ‘L’ ‘R’;

(iv) for five parallel runways: ‘L’ ‘C’ ‘R’ ‘L’ ‘R’ or ‘L’ ‘R’ ‘L’ ‘C’ ‘R’; and

(v) for six parallel runways: ‘L’ ‘C’ ‘R’ ‘L’ ‘C’ ‘R’.

(3) The numbers and letters should be in the form and proportion shown in Figure L-2. The dimensions should be not less than those shown in Figure L-2. Where the numbers are incorporated in the threshold marking, larger dimensions should be used in order to fill adequately the gap between the stripes of the threshold marking.

\[Figure or form omitted from this preview — available in the Avioverse workspace library.]

Figure L-1. Runway designation, centre line and threshold markings

\[Figure or form omitted from this preview — available in the Avioverse workspace library.]

Figure L-2. Form and proportions of numbers and letters for runway designation markings

\[Issue: ADR-DSN/3]

IR · CS ADR-DSN.L.525 — Regulation (EU) No 139/2014 · ED Decision 2016/027/R · Aerodromes Easy Access Rules · EAR revision 13 Mar 2026

[All rules in CHAPTER L — VISUAL AIDS FOR NAVIGATION (MARKINGS)](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-l-visual-aids-for-navigation-markings)

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.