What is Low-Intensity Light?

Low-Intensity Light (Light with Reduced Output) – Airport Lighting Glossary

What Is Low-Intensity Airport Lighting?

Low-intensity airport lighting refers to a dedicated class of airfield luminaires engineered to provide visual guidance with a reduced luminous output, typically under 200 candela (cd) for runway edge lights and above 10 cd for obstruction lights. These systems are mandated for aerodromes with low traffic volumes, general aviation airstrips, temporary or emergency runways, and for marking obstacles where high-intensity solutions are unnecessary or impractical. They are essential for ensuring safe ground and air operations, particularly at locations where cost, energy usage, and environmental impact are critical considerations.

Low-intensity lights are designed and deployed in accordance with international standards, chiefly ICAO Annex 14, FAA AC150/5345-43J (obstruction), FAA AC150/5345-50B (runway/taxiway fixtures), and EN61000-6-4:2019 / EN61000-6-2:2019 for electromagnetic compatibility. These standards ensure that even at lower outputs, the lighting provides reliable visual cues for approach, takeoff, taxiing, and obstacle awareness.

Modern low-intensity systems increasingly utilize LED technology, offering dramatic improvements in efficiency, operational life, and maintenance compared to legacy halogen solutions. This makes them ideal for remote, off-grid, or sustainability-focused operations.

Typical Applications of Low-Intensity Lighting

• Runway Edge, Threshold, and End Lighting: Marking runway boundaries and endpoints at low-traffic or non-instrument airports, providing essential guidance without excessive glare or energy use.
• Taxiway Lighting: Blue edge lights at small aerodromes or private fields to delineate safe taxi routes in low-visibility or nighttime operations.
• Obstruction Lighting: Marking of buildings, antennas, or towers below 45m (150ft), using steady-burning red lights (ICAO Type A/B, FAA L-810) to ensure hazard visibility.
• Portable and Temporary Lighting: Battery or solar-powered units for maintenance, emergency, or rapid deployment at temporary or remote sites.
• Heliport Edge and Approach Lighting: Compact, low-output fixtures to outline helicopter landing zones, particularly in hospital or offshore locations.
• Backup Systems: Rapidly deployable fixtures to maintain minimum lighting during primary system outages.

Types of Low-Intensity Airport Lighting

1. Runway Edge Lights

White lights (sometimes yellow/red near runway ends) with output below 200 cd, available in elevated or inset formats. Used at airports where night operations are infrequent or do not require high output.

• Example: IR908L LED Elevated Runway Edge

2. Runway Threshold Lights

Green lights indicating runway landing thresholds, visible from the approach direction only.

• Example: IR901L LED Inset Runway Threshold

3. Runway End Lights

Red lights denoting the end of the usable runway, visible only from the departing direction.

• Example: IR905L LED Inset Runway End

4. Threshold/End Combination Lights

Dual-purpose fixtures offering green threshold lighting in one direction and red runway end lighting in the opposite, minimizing fixture count.

• Example: IR907L LED Inset Threshold/Runway End

5. Taxiway Edge Lights

Blue fixtures marking taxi routes at smaller airports, available in elevated or inset versions for various ground conditions.

• Example: IR906L LED Elevated Inner Threshold/Runway End

6. Obstruction Lights (Low-Intensity)

Steady red lights for marking obstacles below 45m, meeting ICAO Type A/B/E and FAA L-810 standards.

• Example: PULSAR Low Intensity Obstruction Light
• Example: AV-OL-LI Low Intensity Obstruction Light – Avlite

7. Portable Lighting

Battery or solar-powered lights for temporary runways, displaced thresholds, or emergencies, featuring quick deployment and rugged construction.

• Example: SP-102 Portable Runway Edge Light
• Example: SP-102 Portable Obstruction Light

Key Features and Technical Characteristics

• Light Source: Predominantly LED, offering >100,000 hours of service and consistent output.
• Construction: Corrosion-resistant materials (aluminum, stainless steel, UV-stabilized polycarbonate), sealed for harsh environments (IP65–IP67).
• Power Consumption: Highly efficient, supporting grid, battery, or solar operation.
• Photometric Consistency: Precision optics ensure compliance with chromaticity and intensity standards.
• Modular Design: Interchangeable optical heads, batteries, and mounting for easy maintenance and flexibility.
• Operating Modes: Steady-on, selectable flashing (30/60/120 FPM), dusk-to-dawn, NVG compatibility.
• Control & Monitoring: Integrated diagnostics, discrete I/O for system integration, remote alarms (especially for obstruction lights).

Sample Technical Specifications

Regulatory Compliance and Standards

• ICAO Annex 14, Vol I: Specifies intensity, color, chromaticity, and uniformity for airfield lighting, including low-intensity types.
• FAA AC150/5345-43J: US standard for low-intensity obstruction lighting (FAA L-810).
• FAA AC150/5345-50B: US standard for runway/taxiway lighting fixtures.
• EN61000-6-4:2019 / EN61000-6-2:2019: European EMC emission/immunity requirements.
• Local/Regional Standards: May apply additional requirements, especially near populated areas.

Compliance is validated via type testing, certification, and ongoing quality assurance.

Operational Modes and Control Systems

Low-intensity lighting systems offer:

• Steady-On: Standard mode for continuous night/low-visibility guidance.
• Flashing: Enhanced conspicuity for temporary hazards or displaced thresholds, selectable rates.
• Dusk-to-Dawn: Photocell-activated for automatic operation, ideal for solar/battery units.
• NVG Compatibility: Options for military or special operations.

Advanced systems integrate remote diagnostics, control interfaces, and fail-safe features, ensuring operational reliability.

Summary

Low-intensity airport lighting is a fundamental safety and operational component for small, remote, or temporary airfields and for marking obstacles that do not require high-intensity solutions. These systems, governed by ICAO, FAA, and EN standards, offer reliability, efficiency, and sustainability, supporting safe aviation operations worldwide.