--- title: "CS ADR-DSN.Q.840 – CS ADR-DSN.Q.852: CHAPTER Q — VISUAL AIDS FOR DENOTING OBSTACLES (Certification Specifications and Guidance Material for Aerodrome Design (CS-ADR-DSN) — Issue 7, Aerodromes) — rule index · Avioverse" description: "CS ADR-DSN.Q.840 – CS ADR-DSN.Q.852, Regulation (EU) No 139/2014. Applicability: The specifications for objects to be marked and/or lighted within the…" url: "https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles" --- # CHAPTER Q — VISUAL AIDS FOR DENOTING OBSTACLES Certification Specifications and Guidance Material for Aerodrome Design (CS-ADR-DSN) — Issue 7 · Aerodromes · Regulation (EU) No 139/2014 · CS ADR-DSN.Q.840 – CS ADR-DSN.Q.852 On this page 1. ## [CS ADR-DSN.Q.840 Objects to be marked and/or lighted within the lateral boundaries of the obstacle limitation surfaces](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-840) Applicability: The specifications for objects to be marked and/or lighted within the lateral boundaries of the obstacle limitation surfaces apply only to… 2. ## [GM1 ADR-DSN.Q.840 Objects to be marked and/or lighted within the lateral boundaries of the obstacle limitation surfaces](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-840) The marking and/or lighting of obstacles is intended to reduce hazards to aircraft by indicating the presence of the obstacles. 3. ## [CS ADR-DSN.Q.841 Objects to be marked and/or lighted outside the lateral boundaries of the obstacle limitation surfaces](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-841) Applicability: The specifications for objects to be marked and/or lighted outside the lateral boundaries of the obstacle limitation surfaces apply only… 4. ## [GM1 ADR-DSN.Q.841 Objects to be marked and/or lighted outside the lateral boundaries of the obstacle limitation surfaces](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-841) Other objects outside the obstacle limitation surfaces should be marked and/or lighted if a safety assessment indicates that the object could constitute… 5. ## [CS ADR-DSN.Q.845 Marking of fixed objects](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-845) General: All fixed objects to be marked should, whenever practicable, be coloured but if this is not practicable, markers or flags should be displayed on… 6. ## [GM1 ADR-DSN.Q.845 Marking of fixed objects](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-845) Orange and white or alternatively red and white are preferably used, except where such colours merge with the background. 7. ## [CS ADR-DSN.Q.846 Lighting of fixed objects](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-846) The presence of objects which should be lighted, as specified in CS ADR-DSN.Q.840 and CS ADR-DSN.Q.841 should be indicated by low-, medium- or… 8. ## [GM1 ADR-DSN.Q.846 Lighting of fixed objects](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-846) Guidance on how a combination of low-, medium-, and/or high-intensity lights on obstacles should be displayed is given in Figures GM-Q-1 to GM-Q-8. 9. ## [CS ADR-DSN.Q.847 Lighting of fixed objects with a height less than 45 m above ground level](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-847) Low-intensity obstacle lights, Type A or B, should be used where the object is a less extensive one and its height above the surrounding ground is less… 10. ## [GM1 ADR-DSN.Q.847 Lighting of fixed objects with a height less than 45 m above ground level](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-847) A group of buildings is regarded as an extensive object. \[Issue: 11. ## [CS ADR-DSN.Q.848 Lighting of fixed objects with a height 45 m to a height less than 150 m above ground level](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-848) Medium-intensity obstacle lights, Type A, B, or C, should be used where the object is an extensive one. 12. ## [GM1 ADR-DSN.Q.848 Lighting of fixed objects with a height 45 m to a height less than 150 m above ground level](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-848) Low-intensity obstacle lights, Type A or B, may be used for obstacles higher than 45 m if it is determined to be sufficient. 13. ## [CS ADR-DSN.Q.849 Lighting of fixed objects with a height 150 m or more above ground level](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-849) High-intensity obstacle lights, Type A, should be used to indicate the presence of an object if its height above the level of the surrounding ground… 14. ## [GM1 ADR-DSN.Q.849 Lighting of fixed objects with a height 150 m or more above ground level](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-849) Where, the use of high-intensity obstacle lights, Type A, at night may dazzle pilots in the vicinity of an aerodrome (within approximately 10 000 m… 15. ## [CS ADR-DSN.Q.850](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-850) Intentionally left blank \[Issue: ADR-DSN/3] \[Issue: ADR-DSN/5] 16. ## [GM1 ADR-DSN.Q.850](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-850) Intentionally left blank \[Issue: ADR-DSN/3] \[Issue: ADR-DSN/5] 17. ## [CS ADR-DSN.Q.851 Marking and lighting of wind turbines](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-851) Applicability: When considered as an obstacle a wind turbine should be marked and/or lighted. 18. ## [GM1 ADR-DSN.Q.851 Marking and lighting of wind turbines](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-851) Additional markings and lighting may be provided to the wind turbines if indicated by a safety assessment. 19. ## [CS ADR-DSN.Q.852 Marking and lighting of overhead wires, cables, supporting towers, etc.](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/cs-adr-dsn-q-852) Marking: The wires, cables, etc. to be marked should be equipped with markers; 20. ## [GM1 ADR-DSN.Q.852 Marking and lighting of overhead wires, cables, supporting towers, etc.](https://avioverse.aero/regulations/easa/aerodromes/cs-adr-dsn/chapter-q-visual-aids-for-denoting-obstacles/gm1-adr-dsn-q-852) Where high-intensity obstacle lights, Type B, are used, and it is not possible to locate them as described in CS ADR-DSN.Q.852(d)(2), in some cases, this… Consolidated from the EASA Easy Access Rules (revision 13 Mar 2026, extracted 13 Oct 2026) for convenience. 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