"Where is LIRL typically used?"

"LIRL is installed at small, general aviation, rural, and off-grid airports where traffic is light and night operations are infrequent. It is ideal for airfields lacking advanced electrical infrastructure, as well as for temporary or contingency runways."

"How does LIRL differ from MIRL and HIRL?"

"LIRL provides fixed, low-intensity lighting suitable for visual operations, while MIRL and HIRL offer higher, variable intensity and advanced zoning for airports with more complex traffic and instrument approaches. LIRL is the most cost-effective and simplest to maintain."

"What are the regulatory requirements for LIRL?"

"LIRL systems must comply with ICAO Annex 14, FAA AC 150/5345-46, and equivalent EASA or national standards. These regulations define photometric intensity, color, spacing, construction, and certification criteria for safe and uniform operation."

"Can LIRL systems be solar powered?"

"Yes. Modern LIRL systems increasingly use solar panels, batteries, and LED technology, enabling autonomous operation at airports without reliable grid electricity. These systems offer remote activation and minimal maintenance."

"How are LIRL systems controlled?"

"LIRL can be switched on manually, by automated timers or sensors, or remotely—often via pilot-controlled lighting (PCL), which allows pilots to activate lights using radio transmissions on a designated frequency."

Low Intensity Runway Lighting (LIRL)

LIRL systems use fixed, low-intensity edge lights to mark runways at small airports, enhancing safety and visibility for pilots at night or in low-visibility.

Airport lighting General aviation Runway infrastructure Aviation safety

Low Intensity Runway Lighting (LIRL) and Airport Lighting Systems

Low Intensity Runway Lighting (LIRL) is a foundational technology for airport safety, especially at small or rural airfields. While less conspicuous than the dazzling arrays of lights seen at major international airports, LIRL plays a critical role in ensuring safe night and low-visibility operations at thousands of general aviation and regional airports worldwide.

What is LIRL?

LIRL is a system of fixed, low-brightness runway edge lights. Its essential function is to delineate the edges of a runway, providing visual cues for pilots during approach, landing, takeoff, and taxiing at night or in reduced visibility. LIRL is characterized by:

Low, non-variable luminous intensity (~25 candela)
White edge lighting (with standard color coding for threshold and runway end)
Uniform spacing (not exceeding 60 meters/200 feet)
Simple, robust construction for low maintenance
Suitability for airports without precision instrument approaches or heavy traffic

LIRL is typically found at:

General aviation (GA) airports
Rural and remote airstrips
Temporary or contingency runways (e.g., disaster relief, military)
Heliports (perimeter marking)

Its simplicity, cost-effectiveness, and increasingly autonomous (often solar-powered) design make it the system of choice for airfields where advanced infrastructure is impractical.

Photometric and Chromatic Standards

LIRL intensity and color are standardized globally to ensure pilots receive consistent, unambiguous visual cues, regardless of location.

Intensity:

LIRL: ~25 candela (cd) in the main beam
MIRL: 200–500 cd
HIRL: >1,000 cd

Color:

White: Default for runway edges
Yellow/Amber: Last 600 meters (2,000 feet) or half the runway, caution zone (optional, more common on larger runways)
Red: Runway end, denotes stop/no usable pavement
Green: Threshold (runway start), marks beginning of landing area

All LIRL fixtures undergo rigorous photometric and chromaticity testing to ensure compliance with ICAO Annex 14, FAA AC 150/5345-46, and equivalent standards.

LIRL System Components

A typical LIRL installation includes:

1. Runway Edge Light Fixtures

Robust, weatherproof luminaires (often elevated)
Lamp type: Historically incandescent or halogen; now frequently high-efficiency LEDs
Lenses: Designed for proper photometric output, omnidirectional or bidirectional as needed

2. Power Supply

Grid-powered: Hard-wired, using constant current regulators (CCRs) for consistent output
Solar-powered: Autonomous units with photovoltaic panels, lithium batteries (LiFePO4), and smart controllers. Increasingly popular for remote and off-grid airfields.

3. Control System

Manual: Switched from control tower or ops center
Automated: Timer, photocell, or weather sensor
Pilot-Controlled Lighting (PCL): Pilots activate lights via radio (designated frequency and number of microphone clicks)
Remote: Wireless or GSM app/SMS for solar units

4. Mounting and Protection

Elevated or shallow bases (depending on local requirements)
Resistant to: Weather, wildlife, snow removal, jet blast, and minor impacts

Color Coding and Placement: ICAO/FAA Standards

Color	Placement	Meaning
White	Runway edges	Safe/usable runway surface
Yellow	Last 600m or 2,000ft of runway	Caution—runway end approaching
Red	Runway end	Stop—no usable pavement beyond
Green	Threshold (runway start)	Start of usable runway for landing

Edge lights: 2–10 feet from the runway edge, at ≤200 ft intervals, symmetrical both sides
Threshold/end lights: Perpendicular to runway centerline, green facing approach, red facing departing traffic

Regulatory Framework and Certification

All LIRL systems must comply with rigorous international and national standards:

ICAO Annex 14, Volume I: Global design, photometric, chromatic, and placement requirements
FAA AC 150/5345-46: U.S. technical specifications for runway and taxiway lighting fixtures
EASA, CASA, Transport Canada, NATO STANAG: Regional and military equivalents

Certification:
Manufacturers must pass photometric, chromatic, mechanical, and environmental testing. Certified products are listed by aviation authorities and marked for compliance.

When is LIRL Used?

LIRL is best suited for:

General aviation airports: Private pilots, flying clubs, flight schools
Rural & remote airstrips: Especially where grid access is limited or absent
Temporary/contingency runways: Disaster relief, military, construction
Heliports: Perimeter lighting
Backup/emergency lighting: Secondary to main systems

Limitations:
Not permitted for precision instrument approach runways. Less effective in fog, heavy rain, or snow due to limited brightness.

LIRL vs. MIRL vs. HIRL: At a Glance

Feature	LIRL	MIRL	HIRL
Typical Use	Small, rural, GA airports	Regional, commercial	Major, international
Intensity (cd)	~25 (fixed)	200–500 (variable)	>1,000 (variable)
Color Coding	White/yellow/red at ends	White/yellow (caution)	White/yellow/red (zones)
Control	On/off, PCL, remote	3-step variable	5-step variable
Regulatory	ICAO, FAA, EASA, etc.	ICAO, FAA, EASA, etc.	ICAO, FAA, EASA, etc.
Instrument Use	No	Yes (non-precision)	Yes (precision)
Cost	Lowest	Moderate	Highest
Maintenance	Minimal	Moderate	Intensive

Integrating LIRL with Other Airport Lighting

LIRL is often part of a broader suite of lighting, but at smaller airports, it may be the only system present.

Lighting System	Location	Function	Typical Color
Runway Edge Lights (LIRL)	Runway edges	Define lateral limits	White
Threshold Lights	Runway start	Mark landing area start	Green
End Lights	Runway end	Mark end of usable pavement	Red
Taxiway Edge Lights	Taxiway edges	Differentiate from runways	Blue

At LIRL-only airports, centerline and touchdown zone lights are typically omitted.

Powering LIRL: Electrical and Solar Options

Traditional Electrical LIRL

Uses underground cabling, CCRs, and airport grid power
Higher installation and maintenance cost

Solar-Powered LIRL

Integrated solar panels, LED lights, and batteries
Autonomy up to 30 days on one charge
Remote or wireless control options
Minimal maintenance (battery and panel checks)
Ideal for off-grid airfields or temporary installations

LIRL Control Methods

Manual: Switched by airport staff
Automated: Timer or light sensor
Pilot-Controlled Lighting (PCL): Pilots activate lights by keying the radio on a specified frequency (e.g., 5 clicks within 5 seconds = lights on for 15 minutes)
Remote: Wireless or GSM control via app or SMS (common with solar LIRL)

This flexibility allows LIRL to serve diverse operational needs and staffing levels.

Maintenance and Inspection

LIRL systems require:

Regular alignment and placement checks
Functionality tests (bulb/LED operation, battery status for solar)
Cleaning (lenses, solar panels, removal of debris)
Inspection after severe weather (corrosion, impact, damage)
Replacement of failed components as per manufacturer recommendations

Routine maintenance ensures continued compliance and operational safety.

Pilot Usage and Interpretation

Pilots must understand LIRL’s cues for safe night operations, including:

Continuous white edge lights: Safe, usable runway
Yellow (if present): Caution, approaching runway end
Red: Absolute stop, end of runway
Green at threshold: Start of landing surface

Pilot-Controlled Lighting (PCL): Enables after-hours access at non-towered airports, supporting medevac, emergency, or charter flights.

Mnemonics

White on the Edge, All’s Well Ahead: Continuous white edge lighting indicates safe runway.
Yellow Means Caution: Nearing the end; prepare to stop or go around.
Red Means Stop: Do not proceed beyond runway end.

Glossary of LIRL and Airport Lighting Terms

Term	Definition
Runway Edge Lights	Lights marking the boundary of the runway—LIRL, MIRL, or HIRL
Threshold Lights	Green lights marking the start of the usable runway
Runway End Lights	Red lights marking the end of the usable runway
Taxiway Edge Lights	Blue lights marking taxiway boundaries
Photometric Intensity	The brightness of a light, measured in candela (cd)
Chromaticity	The color of the light, defined by precise coordinates for aviation standards
Constant Current Regulator	Device ensuring steady current and brightness in electrical lighting circuits
Pilot-Controlled Lighting	System allowing pilots to activate airfield lights remotely via radio
ICAO Annex 14	International Civil Aviation Organization’s standard for aerodrome design and ops
FAA AC 150/5345-46	U.S. specification for airport lighting equipment

Low Intensity Runway Lighting (LIRL) remains a cornerstone of safe, accessible air transport at smaller airfields worldwide. Its reliability, simplicity, and adaptability—especially with modern solar-powered options—make it essential for the ongoing viability of general aviation and rural connectivity.

For more information or to discuss upgrading your airfield with advanced LIRL solutions, contact us or schedule a demo .

Frequently Asked Questions

Where is LIRL typically used?: LIRL is installed at small, general aviation, rural, and off-grid airports where traffic is light and night operations are infrequent. It is ideal for airfields lacking advanced electrical infrastructure, as well as for temporary or contingency runways.
How does LIRL differ from MIRL and HIRL?: LIRL provides fixed, low-intensity lighting suitable for visual operations, while MIRL and HIRL offer higher, variable intensity and advanced zoning for airports with more complex traffic and instrument approaches. LIRL is the most cost-effective and simplest to maintain.
What are the regulatory requirements for LIRL?: LIRL systems must comply with ICAO Annex 14, FAA AC 150/5345-46, and equivalent EASA or national standards. These regulations define photometric intensity, color, spacing, construction, and certification criteria for safe and uniform operation.
Can LIRL systems be solar powered?: Yes. Modern LIRL systems increasingly use solar panels, batteries, and LED technology, enabling autonomous operation at airports without reliable grid electricity. These systems offer remote activation and minimal maintenance.
How are LIRL systems controlled?: LIRL can be switched on manually, by automated timers or sensors, or remotely—often via pilot-controlled lighting (PCL), which allows pilots to activate lights using radio transmissions on a designated frequency.

Upgrade Your Runway Lighting

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