Obstruction lighting systems certified by the Federal Aviation Administration (FAA) help businesses and government agencies of all kinds satisfy requirements for making physical objects more obvious to aviators. Among those businesses and agencies are owners of improved real estate, airport operators and owners of telecommunications towers, such as cell towers and broadcast towers. Examples of objects that may require obstruction marking include communications towers, wind turbines, tall structures, chimney stacks, flare stacks, water tanks and buildings.
Towers more than 199 feet tall have to be marked as aviation obstructions. Other, shorter towers also may require marking if they are near enough to airports. FAA regulations specify distances and heights in relation to airport boundaries and flight paths.
The regulations offer a choice between using paint or lights to mark towers during daytime hours. Lights must be used to mark towers during nighttime hours.
In everyday life, you may have noticed a wide variety of types of lights or lamps used for lighting. Examples include incandescent, compact fluorescent, halogen, metal halide, light-emitting diode (LED), fluorescent, neon, high-intensity discharge and low-pressure sodium. For decades, incandescent lights made up the overwhelming majority of lights used to mark aviation obstructions. More recently, the use of LED lights for obstruction marking has become popular, and the reasons are many.
With LED lights, except for the lights themselves and wiring, the entire system is installed at ground level, eliminating the need for climber repair. The tower itself hosts no active components, which reduces the chance of severe damage to illumination systems.
Within the system controller, the use of onboard redundancies for critical components, such as the power supply driver circuit and the flash circuit, reduce the chance of malfunctions. With special filter design and the use of multiple small capacitors, it is possible to eliminate electromagnetic interference and radio-frequency interference (EMI/RFI) noise from the equipment, including any noise from the antenna.
When lighting systems are strategically designed with redundancy in mind, each component mitigates safety problems to ensure system reliability. Effective steps exclude the DC power supply from the beacon and include lightning surge protection with system components to provide quicker reactions.
Reliability is also improved when monitoring and control circuitry, the photocell and capacitors are not placed in the beacon. It also is important not to situate processor-to-processor communications between the beacon and the power control unit.
Redundancies increase a lighting system’s longevity and offer monetary and energy-saving advantages. Lighting systems last longer when they are specifically fabricated to maximize operability and increase longevity while decreasing maintenance requirements through a user-friendly interface. Engineered redundancies allow lighting systems to maintain effectiveness, even in the unlikely event of a component failure.
Some examples of useful redundancies in a lighting system’s power control unit include the use of two DC power supplies, two driver circuits, two flash circuits and additional capacitors in case some should fail. It helps to equip the power control unit, the beacon and alarm circuits with passive surge protection of the resonant circuit type to isolate transient surges that may find their way onto these inputs. A resonant circuit combines capacitance and inductance such that a periodic electric oscillation reaches its maximum amplitude.
IR Technology Standard
According to the FAA, pilots using night vision imaging system (NVIS) equipment that filters adverse effects of cockpit lighting may not be able to see LED-based obstruction lighting. An inability to see obstruction lighting poses a safety risk to pilots, passengers and ground personnel. The use of night vision goggles (NVGs) offsets the risk by amplifying ambient light, improving pilots’ vision to allow them to see terrain and other possible hazards in the dark. Infrared (IR) technology allows obstruction lighting to be seen with NVIS equipment. Obstruction lighting systems equipped with IR technology ensure the safety of all who rely on the lighting systems.
Designing and setting flash rates and flash markers in a way that complies with avian safety helps lighting systems to avoid posing risks to migratory birds and other avians. It is a way to improve the safety for everyone, including our feathered friends.
Audrey May is marketing manager at Drake Lighting. The company distributes ETL-certified FAA obstruction lighting, electrical supplies and monitoring products and systems. Drake Lighting is the American distributor for Technostrobe products. This article ran in the August 2019 issue of AGL Magazine.