Obstruction Lighting – Aircraft Warning Lights

Lights on tall or hazardous structures that warn pilots of an obstacle at night and in poor visibility. ICAO Annex 14 defines the colours, intensities and flash patterns; national authorities decide which structures need them.

To mark obstacles for aircraft and helicopters: buildings, telecom and broadcast masts, wind turbines, chimneys, cranes, bridges, power lines and offshore structures. They are the night-time counterpart of day markings such as red and white paint.

Not all buildings. ICAO Annex 14 generally treats structures of 150 m or more above ground as obstacles that should be marked and lit, and lower structures need lights when they stand near an aerodrome or penetrate its protected surfaces. National authorities set the exact thresholds and can require lighting on lower structures, so check with yours — we help with the specification.

The lights plus everything that makes them work reliably: power supply (mains or solar), day/night switching, flash synchronisation and failure monitoring. For tall structures it often combines medium intensity lights on top with low intensity lights at intermediate levels.

LED lights use a fraction of the power of incandescent lamps — our solar low intensity light draws 0.5 W — and last many years without lamp replacement, which matters on structures that are hard to reach. Colour and intensity also stay stable over their life.

Daytime markings that make an obstacle visible without lights: alternating red and white or orange and white bands on masts and chimneys, chequered patterns on large surfaces, and markers such as spheres on overhead wires. On some structures white flashing medium intensity lights can replace painted marking, if the authority allows it.