Obstruction Lighting

Aviation obstruction lights are an essential safety precaution on tall structures, including buildings, towers/antennas, wind turbines and others. High-intensity obstruction lights placed at the tops of tall structures ensure 24-hour visibility of the potential hazard to overflying aircraft, with further lights at intervals to mark the full profile of hazards over 45m tall.

Durable, hard-wearing LED obstruction lights offer reliable safety with a long lifespan and minimal routine maintenance. Just regularly check the integrity of the unit, the power supply and the intensity of the light output, to remain compliant with FAA and ICAO regulations.

FAA obstruction lighting requirements are generally based on 14 CFR Part 77 from the Code of Federal Regulations. This applies to structures over 200 feet (61m) tall, with some specific rules for sloping land and nearby to highways and railroads.

There may also be circumstances under which the FAA would recommend aviation obstruction lighting for a structure less than 200 feet tall. Additional advice is issued as an FAA Advisory Circular with the prefix AC 70/7460-1.

By their nature, wind turbines are usually installed in exposed or remote locations, both onshore and offshore. Adequate obstruction lighting is essential to signal the position and height of turbines to passing aircraft, and to reduce the risk of a collision.

This is especially important on large wind farms, where there may be hundreds of turbines significantly taller than the surrounding landscape and architecture. Lighting requirements can vary depending on the height of the structure; the CAA notes that turbines can range from 30m to over 150m tall.

Aviation obstruction lights are built to withstand heavy weather, including wide ranges of temperature and relative humidity. LED obstruction lights in particular have a long expected lifespan with minimal maintenance. Regular checks should be carried out to ensure the luminaires are still providing the required intensity and to remove any dirt that has accumulated on the dome.

Maintenance checks should also ensure that the power supply is in good condition and the overall integrity of the unit is still good, to reduce any risk of outage or failure. Some units are fitted with two LED circuits in the same fixture, with automatic changeover to the backup light in the event of a fault.

ICAO Annex 14 sets out the full regulations for aviation obstruction lighting. Chapter 3.3 details procedures for lighting of obstructions at night, with additional lights placed at intervals on structures over 45m tall. FAA regulations should also be considered. These are updated via FAA Advisory Circulars with the document prefix AC 70/7460-1.

There are several differences in specifications, for example:

• Low intensity: Obstacles up to 45m high, minimum intensity 10cd
• Medium intensity: Height 45-150m, intensity 2,000cd (night) and 20,000cd (day)
• High intensity: Height over 150m, intensity 2,000cd (night) and 200,000cd (day)

Full details are available as product datasheets in downloadable PDF format, for easy future reference.

Obstruction lights are available as high-intensity LED luminaires, as well as ‘traditional’ bulbs such as neon or GLS. Recent advancements in LED technology have allowed the development of LED obstruction lights that comfortably meet the minimum required brightness levels and offer an extended lifespan with minimal maintenance.