Obstacle Marking and Lighting (Annex 14 Chapter 6)

Obstacle marking and lighting (Annex 14 Chapter 6)

Masts, chimneys, power lines and wind turbines are a real hazard for VFR pilots flying at low level — especially in poor visibility or at night. ICAO Annex 14 Vol I, Chapter 6 (Visual Aids for Denoting Obstacles) standardises how such obstacles are painted, marked and lit so that you can spot them in time. For the exam you must know the colour schemes, the three intensity classes of obstacle lights and their applications.

Why obstacles are marked

Marking (colours, flags, markers) makes obstacles conspicuous by day; lighting makes them conspicuous by night and in low visibility. Together they reduce the risk of collision with obstacles and of CFIT (controlled flight into terrain) in the vicinity of aerodromes and along approach and departure paths.

Colour marking of obstacles

Rules of thumb from Annex 14:

• Each colour band should be about 1/7 of the object's height, minimum 0.5 m.
• Where colour marking is impracticable (e.g. transparent or moving structures), flags or markers are displayed instead.

Obstacle lights: three intensity classes

Annex 14 defines low-, medium- and high-intensity obstacle lights. Broadly, the taller the obstacle, the more intense the lighting required.

1. Low-intensity obstacle lights

• Type A: steady red, approx. 10 cd; Type B: steady red, approx. 32 cd.
• Used on low obstacles (up to about 45 m above ground) or to supplement higher-intensity lights on larger structures.

2. Medium-intensity obstacle lights

• Type A: white flashing, 20 000 cd (reduced to 2 000 cd at night); 20–60 flashes/min.
• Type B: red flashing, 2 000 cd; 20–60 flashes/min.
• Type C: red steady, 2 000 cd.
• Used on obstacles between about 45 m and 150 m above ground.

3. High-intensity obstacle lights

• Type A: white flashing, 200 000 cd (day), 20 000 cd (twilight), 2 000 cd (night) — for objects higher than 150 m above ground level.
• Type B: white flashing — for towers supporting overhead wires or cables (e.g. power-line pylons at valley or river crossings).

High-intensity lights are typical of very tall structures such as broadcast towers and tall wind turbines.

Configuration on tall objects: lights are arranged in levels — at the top, and at intermediate levels (e.g. middle and lower thirds) so that the whole extent of the obstacle is visible; very tall objects carry additional intermediate levels.

Marking of wires and cables

Overhead power lines, antenna stays and similar cables are marked with spherical markers:

• Diameter at least 60 cm.
• Colour red, white or orange-red, alternating where several markers are fitted.
• Spacing along the cable typically 30–40 m, depending on marker size and cable height.

Wind turbines

• Rotor blades are painted white or light grey, with red bands at the blade tips.
• The tower carries alternating red/white marking (typically a red band around the middle section).
• Lighting: red steady or flashing lights on the nacelle and tower; turbines higher than 150 m additionally carry white high-intensity flashing lights.

Europe and Germany

EU-wide application is via Regulation (EU) No 139/2014 (Part-ADR) and CS-ADR-DSN Subpart Q (Visual aids for denoting obstacles), which mirror Annex 14 Chapter 6. In Germany the following national details apply:

• The Allgemeine Verwaltungsvorschrift zur Kennzeichnung von Luftfahrthindernissen (AVV Kennzeichnung) of the BMDV sets out the national implementation.
• Structures of 100 m or more above ground are generally subject to marking obligations (with exceptions in built-up areas).
• Wind turbines: marking from a total height of 100 m; lighting from 150 m.
• Demand-based night marking (Bedarfsgesteuerte Nachtkennzeichnung, BNK): modern wind farms switch their obstacle lights on only when air traffic is detected nearby (transponder or radar based), reducing light pollution — introduced via §46 LuftVG.
• The owner/operator of the obstacle is responsible for marking; oversight lies with the state aviation authority (Landesluftfahrtbehörde). Significant obstacles are published in AIP Germany ENR 5.4.

Exam essentials

• Obstacle marking uses red/orange-red, alternating red-white (or orange-white) bands, or a checkerboard for broad objects; each band is about 1/7 of the object height.
• Low-intensity obstacle lights are red (Type A approx. 10 cd, Type B approx. 32 cd) and serve obstacles up to about 45 m AGL.
• Medium-intensity lights serve obstacles of about 45–150 m AGL: Type A white flashing (20 000 cd), Type B red flashing (2 000 cd), Type C red steady (2 000 cd).
• High-intensity Type A lights are white flashing and mark objects higher than 150 m AGL; high-intensity Type B lights are white flashing and mark towers supporting overhead wires or cables.
• Cables are marked with spherical markers of at least 60 cm diameter in red, white or orange-red.
• In Germany, structures from 100 m AGL generally require marking; wind turbines above 150 m require lighting, increasingly as demand-based night marking (BNK) under §46 LuftVG.