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CS ADR-DSN.Q.851 Marking and lighting of wind turbines

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

IRImplementing rule

CS ADR-DSN.Q.851Marking and lighting of wind turbines

(a)Applicability: When considered as an obstacle a wind turbine should be marked and/or lighted.

(b)Marking: The rotor blades, nacelle and upper 2/3 of the supporting mast of wind turbines should be painted white, or if after a safety assessment, it is determined that other colour will improve safety.

(c)Lighting:

(1)Where lighting is deemed necessary for a single wind turbine or short line of wind turbines, the installation should be in accordance with paragraph (c)(2)(v) below, or as determined by a safety assessment.

(2)When lighting is deemed necessary in the case of a wind farm (i.e. a group of two or more wind turbines), the wind farm should be regarded as an extensive object and lights should be installed:

(i)to identify the perimeter of the wind farm;

(ii)respecting the maximum spacing, in accordance with CS ADR-DSN.Q.846(i), between the lights along the perimeter, or if after a safety assessment, it is determined that a greater spacing can be used;

(iii)so that, where flashing lights are used, they flash simultaneously throughout the wind farm;

(iv)so that, within a wind farm, any wind turbines of significantly higher elevation are also identified wherever they are located; and

(v)at locations prescribed in (i), (ii) and (iv):

(A)for wind turbines of less than 150 m in overall height (hub height plus vertical blade height), medium intensity lighting on the nacelle;

(B)for wind turbines from 150 m to 315 m in overall height, in addition to the medium intensity light installed on the nacelle, a second light serving as an alternate should be provided in case of failure of the operating light; the lights should be installed to assure that the output of either light is not blocked by the other;

(C)in addition, for wind turbines from 150 m to 315 m in overall height, an intermediate level at half the nacelle height of at least three low intensity Type E lights, as specified in CS ADR-DSN.Q.846(c), that are configured to flash at the same rate as the light on the nacelle; low-intensity Type A or B lights may be used if an safety assessment shows that low intensity Type E lights are not suitable.

(3)The obstacle lights should be installed on the nacelle in such a manner as to provide an unobstructed view for aircraft approaching from any direction.

[Issue: ADR-DSN/3]

IR · CS ADR-DSN.Q.851 — Regulation (EU) No 139/2014 · ED Decision 2016/027/R · Aerodromes Easy Access Rules · EAR revision 13 Mar 2026

All rules in CHAPTER Q — VISUAL AIDS FOR DENOTING OBSTACLES

Consolidated from the EASA Easy Access Rules (revision 13 Mar 2026, extracted 17 Aug 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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