Obstacle lighting provides visibility of tall objects from long distances, therefore it plays a significant role in ensuring air traffic safety. Not only the light intensity is important here, but also the color and type (solid, flashing). Due to the fact that they are installed outdoors and at high altitudes, they must simultaneously meet many conditions. What do the individual lights mean? What do the regulations say about them? You can learn all this from this article.
Provisions regarding obstacle lighting
Obstacle lighting must be used in accordance with applicable ICAO (International Civil Aviation Organization) regulations. There are also separate regulations in individual countries. For example, in the United States, the FAA (Federal Aviation Administration) regulations also apply.
Air obstacles
Air obstacles are ground, natural or artificial objects that can, due to their height, size or low contrast with the background, create a hazard in air traffic. Such constructions or structures may be located near the airport, but also in any other place.
What objects are we talking about?
Air obstacles include, but are not limited to:
- Towers,
- Skyscrapers,
- Bridges,
- Masts,
- Chimneys,
- Antennas,
- Land elevations.
Obstacle light intensity levels
Lights are marked with three levels of intensity: low, medium and high. Low-intensity lights are used to mark objects up to 45 meters high. Higher buildings, constructions or natural objects require marking with medium intensity lights. In contrast, high-intensity lights are used for objects that cannot be marked with signs in the form of painting.
Types of obstacle lighting
In the case of lights used to mark obstacles to air traffic, not only their intensity is important. We divide them into three additional types: A, B, C. Each of them defines the color and type of light.
- Type A obstacle lighting – solid white,
- Type B obstacle lighting – flashing light, red
- Type C obstacle lighting – solid red light.
Now let’s see what lights are used for each type of air obstacle.
Low intensity obstacle lighting
If the height of the obstacle exceeds 45 meters, it is marked with low intensity A or B type lighting. Type A lighting is used where type B lighting could cause blindness to the aircraft operator. Both types of lighting are used to mark objects located at the airport. We find them on flight control towers, radars, masts, antennas, chimneys, radio and television towers, tall buildings, bridges, transmission lines, wind turbines, tall buildings and measuring masts.
Medium intensity obstacle lighting
Obstacles with a large area and those whose height exceeds 45 meters are marked with medium intensity obstacle lighting of all three types: A, B and C. The intensity of the emitted light is in the range from 2000 cd (candelas) to 20 000 cd.
High intensity obstacle lighting
High intensity obstacle lighting is used for objects whose height exceeds 150 meters. It provides the best visibility both during the day and at night. The sample high intensity light flashes 40 times per minute and provides intensity from 2,000 cd at night, through 20,000 cd at dusk, to 270,000 cd during the day.
Monitoring and maintenance
Safety of air navigation requires that obstacle lighting monitoring methods should also be subject to appropriate regulations. Such lighting should be replaced when it reaches 75% of its life, or immediately after irregularities occur, as well as in the event of cracks or accumulated dirt. If obstacle lighting is not equipped with automatic monitoring, it should be inspected every 24 hours.
Obstacle lighting – work in difficult conditions
Obstacle lighting is installed in places with difficult conditions. Therefore, it should meet a number of requirements that will ensure them a long and reliable operation.
What advantages are expected from obstacle lighting:
- Durability,
- Reliability,
- Low energy consumption,
- Ease of installation,
- Resistance to extreme temperatures,
- Corrosion resistance,
- Wind resistance,
- Impact resistance,
- Suitably low weight and size.
In addition, it is important that the stream of emitted light is constant, regardless of external factors or working time. Many of these conditions are met by lighting based on LED technology, which is why such lights are most often used to illuminate air obstacles.