ADLS: Aircraft Detection Lighting System for Wind Turbines

Planning and system design of a transponder-based ADLS-System

What BNK and ADLS mean, how they work, and why Lanthan, as a co-inventor of the BNK transponder, continues to this day to supply open-system, BNK/ADLS-compatible obstacle lighting.

BNK stands for Demand-Driven Night Marking—a system that activates the obstacle lights on wind turbines, high-rise buildings, and other aviation obstacles only when an aircraft is actually approaching. Internationally, the term ADLS (Aircraft Detection Lighting System) is commonly used for this purpose—both terms describe the same operating principle.

Instead of flashing throughout the entire night, the system detects an approaching aircraft via radar, transponder, or camera and only then activates the lighting. This significantly reduces light pollution and the burden on residents without compromising flight safety.

Co-invented by Lanthan

Lanthan has been working on the development of the transponder-based BNK/ADLS since 2004 — one of the first methods for reliably detecting approaching aircraft via transponder signals in order to control the lighting system as needed. Since 2010, the method has been successfully in practical use in first systems at wind farms.

In April 2020, Lanthan contributed the technology to the newly founded Lanthan Safe Sky (LSS) — together with fellow shareholders Recase and Air Avionics, who have jointly continued to develop the method ever since.

Lanthan itself does not manufacture or sell BNK/ADLS control systems. What Lanthan supplies are the obstacle lighting systems themselves — designed to work with any standard BNK/ADLS system, regardless of the control system manufacturer. When it comes to implementation, Lanthan provides manufacturer-neutral advice and arranges comprehensive packages — whether through LSS or any other provider on the market.

Why Open-System Lighting Matters

Anyone investing in a BNK/ADLS system commits to a control system provider—but not necessarily to a specific manufacturer of the obstacle lights themselves. Lanthan lights are deliberately designed to be manufacturer-independent and open-system:

  • Compatible with common BNK/ADLS control systems on the market
  • No dependence on a single control system provider
  • Future-proof in the event of a provider change or system expansion
  • Certified according to German and international regulations (AVV, ICAO)

This makes Lanthan the ideal partner for operators seeking BNK/ADLS-compatible obstacle lighting without being tied to a specific control solution.

FAQ on all BNK / ADLS topics

What does the abbreviation ADLS stand for?

ADLS stands for demand-responsive night-time marking. The system activates the obstacle lighting only when an aircraft is detected, rather than flashing continuously throughout the night. Internationally, the term ADLS (Aircraft Detection Lighting System) is usually used for this.

What is the difference between BNK and ADLS?

Functionally, there is no difference — BNK is the German term, whilst ADLS is the internationally used term for the same principle of demand-driven obstacle lighting.

Is BNK/ADLS mandatory for wind turbines?

Since the 2018 German Energiesammelgesetz, demand-driven night-time marking (BNK/ADLS) has been mandatory in Germany for wind turbines with a hub height of over 100 m.

How does an ADLS system work from a technical point of view?

An ADLS system detects approaching aircraft using radar, transponders or camera/sensor technology, and only activates the obstacle lights when they are close by. Lanthan was involved in the development of the transponder-based ADLS, which has been in operational use since 2010.

Does Lanthan manufacture BNK/ADLS control systems?

No. Lanthan co-invented the ADLS transponder, but does not itself manufacture or distribute any BNK/ADLS control systems. Lanthan supplies obstacle lighting systems that are open-system and compatible with standard BNK/ADLS control systems from any supplier. Lanthan provides advice and arranges comprehensive implementation packages.