LED Airfield Ground Lighting
A complete engineering guide to LED runway, taxiway, approach, PAPI and other airfield lighting systems. LED Airfield Ground Lighting is the application of light-emitting diode technology to airport visual aids used for aircraft movement, approach, landing, take-off and surface guidance. The transition from conventional incandescent sources to LED does not simply mean changing a lamp — an LED airfield light is a complete optical, electrical, thermal and mechanical system. A proper assessment must consider light source, optics, current/driver, thermal management, photometry, alignment, control, power, mechanical integrity and certification together.
What Is LED Airfield Ground Lighting?
LED Airfield Ground Lighting uses semiconductor light sources instead of conventional incandescent lamps for aviation visual aids — runway edge, threshold, runway end, centreline and touchdown-zone lights, taxiway edge and centreline lights, stop bars, runway guard lights, approach lights, PAPI, REIL, airfield signs, obstruction lighting and other visual aids. The exact application depends on the equipment design and applicable standards.
That is the difference between an LED product and an aviation-grade LED lighting system: Light source + optics + current/driver + thermal management + photometry + alignment + control + power + mechanical integrity + certification.
Not Just a Lamp Change
An LED airfield light is a complete optical, electrical, thermal and mechanical system — not a drop-in replacement for an incandescent source.
FAA LED Migration
FAA's January/February 2025 Safety Briefing described an ongoing LED migration program for airport lighting, highlighting LED PAPI and approach-lighting applications.
The Right Question
Not "Is it LED?" — but "Does the complete LED fixture provide the required aviation performance for its intended function?"
Why LED Became Important — and Why It's Not Automatically Better
LEDs offer characteristics that are attractive for airport lighting applications:
LED technology changes the engineering characteristics of the light source, introducing new considerations: spectral distribution, colour saturation, thermal behaviour, driver electronics, dimming, failure modes, optical design and brightness perception.
The correct question is not "Is it LED?" It is: "Does the complete LED fixture provide the required aviation performance for its intended function?"
Incandescent vs LED
The optical and electrical behaviour of the two technologies should not be assumed to be identical.
| Parameter | Incandescent | LED |
|---|---|---|
| Light-generation principle | Heated filament | Semiconductor junction |
| Electrical efficiency | Lower | Generally higher |
| Heat source | Filament | LED junction and electronics |
| Switching | Relatively simple | Electronic |
| Dimming | Conventional current/voltage behaviour | Driver-dependent |
| Colour | Often filter-dependent | Semiconductor/optics-dependent |
| Source life | Relatively shorter | Generally longer |
| Electronics | Limited | Integral or external driver |
| Failure mode | Often filament open circuit | Can include driver, LED string or electronics failure |
LED Light Generation & Array Configuration
An LED emits light when current passes through a semiconductor junction. The light produced is controlled by semiconductor material, junction design, drive current, temperature, optical assembly and manufacturing characteristics. In an airfield light, the LED is only one part of the complete optical chain.
LED Array
An airfield fixture may contain a single LED, multiple LEDs, LED arrays, separate LED channels or redundant LED strings. A multiple-LED array can allow optical output to be maintained even if one element fails — but this behaviour must be established from the product design and applicable test requirements.
Aviation Colour Requirement
Typical aviation colours are white, red, green, blue and yellow, each a function of the visual-aid application. Do not select an LED solely from a consumer lighting colour designation such as "cool white" or "warm white" — the measured aviation colour performance is what matters.
Aviation LED Colour & Human Perception
| Colour | Typical Aviation Applications |
|---|---|
| White | Runway edge, threshold, approach lighting |
| Red | Runway end, obstruction systems, PAPI red sector, stop bars |
| Green | Threshold lighting, taxiway centreline, runway centreline transitions |
| Blue | Taxiway edge visual guidance |
| Yellow / Amber | Caution zones and other coded visual aids per applicable requirement |
Pilots use colour as a coded visual cue, so aviation lighting requires controlled colour characteristics. Two lights can have similar photometric intensity yet appear different to an observer because of differences in spectrum, saturation, background, adaptation and viewing conditions.
FAA research found that LED signal lights can appear brighter than incandescent signal lights at matched nominal luminous intensities, particularly for some aviation colours — making colour and brightness perception directly relevant to LED AGL engineering.
The Four Cs of LED AGL Photometry
Is the aviation colour correct?
Is the intensity correct?
Is the angular distribution correct?
Is the fixture installed correctly?
A common misunderstanding: "more lumens = better airfield light." That is incorrect.
Lumens describe total luminous flux. Candela describes luminous intensity in a direction. Airfield lighting is highly directional, so candela distribution is far more relevant than simply quoting total lumens.
A runway-centreline fixture and a taxiway-edge fixture do not need the same optical pattern.
Optical Design, Contamination & Beam Alignment
Lens Design
A lens can collimate light, shape a beam, redirect light, concentrate intensity, and control vertical and horizontal distribution — a critical photometric component, not just a cover.
Reflector-Based Design
Some systems combine LEDs with reflectors that shape output while controlling direction, spread, peak intensity and optical efficiency. The actual architecture is equipment-specific.
Optical Contamination
Dust, mud, rubber deposits, oil, moisture, salt and construction debris can reduce useful light reaching the required viewing angle. LED does not eliminate the need for optical cleaning.
The beam must be oriented correctly relative to the runway or taxiway geometry. A high-output fixture pointing in the wrong direction is still an incorrectly installed AGL fixture — especially important for in-pavement lights, threshold lights, runway/taxiway centreline, approach lights and PAPI.
LED Driver, Dimming & CCR Compatibility
One of the most important AGL engineering issues is compatibility with the Constant Current Regulator. Traditional series-circuit AGL commonly uses CCR → series circuit → isolation transformer → fixture. An LED fixture must be designed to operate correctly with the intended series-circuit environment — it cannot be treated like a simple low-voltage LED lamp. The fixture may contain a rectifier, current converter, driver, protection circuit, control electronics, LED array and thermal monitoring; the detailed interface is manufacturer-specific.
CCR-fed series circuit interfacing with an LED fixture's internal electronics
Thermal Management
Heat from the LED and driver flows through a spreader and finned body to the air.
AGL Visual Encyclopedia: Heat management system Overheating
LEDs are more efficient than incandescent sources, but they still generate heat concentrated around the LED junction, PCB and driver electronics — and that heat must be removed. Thermal design is also photometric design, because junction temperature affects optical output, efficiency, colour characteristics, lifetime and reliability.
Typical thermal path — any weak point in this chain can increase junction temperature
Inset Fixture Thermal Challenge
Inset lights are surrounded by pavement or mounting hardware, so heat cannot always be rejected as with an exposed elevated fixture — housing conduction, pavement temperature, ambient temperature, heat dissipation path and duty cycle must all be accounted for.
High Ambient Temperature
High ambient temperature reduces the temperature difference available for heat rejection, so the system may operate with higher junction temperature — particularly important in hot climates.
Thermal Protection
Some fixtures incorporate thermal sensors, current reduction, shutdown or driver protection. The exact behaviour depends on the manufacturer — understand what happens during an over-temperature event.
LED Efficiency & Power Consumption
System-Level Efficiency
Airport power → fixture input → driver → LED → optics → useful aviation intensity. A high-efficiency LED chip does not automatically mean a high-efficiency aviation fixture.
FAA LED PAPI Result
FAA reporting on its LED PAPI program described observed reductions of approximately 60–70% compared with the older PAPI equipment involved — a program-specific reported result, not a universal figure for every LED conversion.
Efficiency ≠ Compliance
An LED fixture may consume less power but still fail due to wrong optical distribution, poor alignment, incorrect colour, dirty optics, driver fault or thermal degradation.
LED Fixture Types & Their Engineering Considerations
An LED runway fixture in section, with a panel comparing it to a lamp-based fixture.
AGL Visual Encyclopedia: LED runway fixture LED beacon
Several LED chips on a metal-core board, mounted through a thermal interface to the fixture body.
AGL Visual Encyclopedia: LED module in a fixture LED module LED driver in a fixture
Runway & Taxiway Edge
Colour, intensity, beam distribution, spacing, alignment, inset/elevated configuration, mechanical strength and power interface all apply — taxiway edge specifically needs correct blue aviation colour and consistent pattern.
Threshold & Runway End
Threshold lights communicate the beginning of the landing portion; runway-end lighting has a different visual function. LED can provide precise colour and output, but the fixture must still meet the requirements for its specific function and viewing direction.
Centreline & Touchdown Zone
Highly directional and geometrically sensitive — beam orientation, horizontal spacing, vertical distribution, colour, pavement installation, mechanical loading and heat dissipation must work together as a system.
Stop Bars & Guard Lights
Safety-critical visual aids — red output, beam direction, switching, interlocking, monitoring, fail-safe behaviour, flashing pattern and synchronization must be treated as a complete control-and-lighting system.
Approach Lighting
Contains many individual units with carefully defined geometry — LED conversion requires more than replacing light sources; the complete optical arrangement must preserve the intended approach-lighting pattern.
LED PAPI
Not just an LED box — red/white transition, beam elevation, horizontal alignment, unit relationship, intensity, colour and stability all apply. Changing to LED without validating the resulting beam geometry can affect system performance.
LED REIL
Critical parameters: flash characteristics, intensity, beam angle, synchronization, colour and control.
Airfield Signs
Luminance, colour, letter/legend visibility, uniformity, power consumption, driver reliability and day/night operation.
Obstruction Lighting
Low/medium/high-intensity systems, with exact characteristics depending on the applicable aviation requirement and obstacle application. LED spectral characteristics can also have night-vision-goggle implications.
Brightness Perception & Avoiding Excessive Brightness
Two sources with nominally similar intensity can produce different subjective brightness. FAA research found LED signal lights can appear brighter than corresponding incandescent sources at matched luminous intensities for studied aviation colours — relevant when designing or evaluating intensity levels.
An AGL fixture should not simply be driven as brightly as possible. Excessive apparent brightness can create glare, visual distraction, reduced contrast and difficulty identifying adjacent cues. The required intensity should come from the applicable design and photometric requirements.
Photometric Measurement, Goniophotometry & Field vs Lab Testing
Photometric Measurement
A complete assessment may include horizontal angles, vertical angles, intensity, colour, beam shape, peak locations, cutoff behaviour and uniformity where applicable.
Goniophotometry
A goniometric system measures the fixture over defined angular positions — useful for intensity curves, beam shape, angular distribution, PAPI transitions and runway light characterization.
Laboratory vs Field
Laboratory testing measures controlled equipment performance; field testing measures installed-system performance and can detect misalignment, optical damage, reduced output, dirt or wrong fixture type. A fixture that passes a factory test can still be incorrectly installed in the field.
LED output = healthy. Driver = healthy. Battery/CCR = healthy. But fixture azimuth = incorrect.
Result: operational visual performance = incorrect. This is one of the most important AGL troubleshooting principles — for a directional aviation light, peak candela ≠ complete compliance.
Colour Measurement & Shift with Temperature and Aging
LED optical characteristics can change with temperature — small wavelength changes, intensity variation and driver behaviour changes are all possible. LED aging can affect intensity, spectrum, phosphor performance and optical materials. For aviation systems, the relevant performance should remain within applicable limits throughout the fixture's service life — long-term LED performance should therefore be considered at system-design stage.
LED Lifetime, L70 & Complete Fixture Life
LED manufacturers often provide lifetime estimates in terms such as L70, L80, operating hours and junction temperature. These are useful engineering parameters, but they do not equal the service life of the complete AGL fixture.
L70 generally refers to the point at which light output has fallen to approximately 70% of an initial reference level under a defined methodology — it should not be confused with fixture failure, FAA qualification, aviation serviceability or photometric compliance.
Inrush, Harmonics, EMC & Surge Protection
Inrush Current
Electronic drivers can have startup-current characteristics different from traditional lamps — evaluate inrush, startup time, CCR behaviour, protective-device coordination and multiple simultaneous fixture startup.
Harmonics & Power Quality
Electronic drivers can interact with the electrical system through harmonic currents, power factor, switching transients and electromagnetic emissions — reviewed where required by project specification and system design.
EMC
Conducted emissions, radiated emissions, immunity to external disturbances and interaction with nearby systems all matter in airport environments containing sensitive equipment.
Surge Protection
LED electronics can be more sensitive to semiconductor damage than simple filament circuits — surge protection, grounding and equipment design must be considered together.
Lightning Environment
Long cables, field wiring, control circuits and power supplies are potential pathways for transient energy across large outdoor lighting systems — protection must match system architecture.
Series Circuit Transients
A series AGL circuit can experience transients from switching, insulation events, cable faults, lightning and CCR behaviour — the LED fixture's input circuitry must be designed for its intended series-circuit environment.
Isolation Transformers, L-823 Connectors & Cable Insulation
Where an LED fixture is connected to a conventional series circuit, the isolation transformer may remain part of the system: CCR → primary series circuit → isolation transformer → LED fixture input → LED driver → LED array. LED does not eliminate the isolation transformer automatically.
Conventional series-circuit AGL installations may use airport cable connector systems such as L-823-type connectors — FAA currently lists AC 150/5345-26E for L-823 plug and receptacle cable connectors. The LED fixture must remain compatible with the installation's connector, transformer lead, cable and mechanical arrangement.
The LED fixture may have a low internal operating voltage even though the primary AGL circuit is at high voltage relative to ground — fixture input design and series-circuit design must be treated separately.
Mounting, Sealing & Environmental Protection
Five seals keep water and dirt out of an elevated light.
AGL Visual Encyclopedia: Sealing system Moisture ingress Water ingress prevention
Inset vs Elevated Fixtures
Inset lights face aircraft wheel loading, water, dirt, heat, impact, vibration and pavement movement. Elevated fixtures have different requirements: structural support, frangibility, wind, snow/ice, jet blast and mechanical alignment.
Frangibility
An LED fixture is not automatically frangible merely because its housing is small — the complete support arrangement should be assessed under the applicable aerodrome requirements.
Sealing, Water Protection & Condensation
Cable glands, housing joints, lens interfaces, connectors, breathing systems and battery compartments are potential moisture entry points. A fixture can be externally sealed yet still experience internal condensation from temperature cycling, pressure changes or trapped assembly moisture.
Optical Window
The window should maintain transparency, mechanical integrity, UV resistance, colour stability and environmental resistance — its degradation can reduce photometric performance even when the LED source is healthy.
Water Drainage
In-pavement fixtures must interact correctly with the light base, drainage, pavement, transformer compartment and connector — water accumulation can contribute to insulation and corrosion problems.
UV, Salt & Loading
UV exposure degrades plastics, lenses, seals, cable insulation and housing finishes; salt affects fasteners, connectors and electronics at coastal airports; inset fixtures must maintain strength and flushness under aircraft wheel loading, and elevated fixtures must withstand jet blast airflow and vibration.
Reliability, Thermal Cycling & Failure Modes
Daily operation creates thermal cycling — cold start → heating → steady state → cooling — that can stress solder joints, capacitors, PCB, thermal interfaces and driver components. Long-term reliability therefore depends on more than the rated LED hours.
| Symptom | Possible Area |
|---|---|
| Light OFF | Power, driver, control |
| Low intensity | Driver, LED, optics, thermal |
| Flickering | Driver, control, connection |
| Wrong colour | LED, optics |
| Intermittent | Thermal, connection, electronics |
| One sector weak | LED channel, optical path |
| Beam shifted | Mechanical alignment |
| Uneven output | LED array, optics, contamination |
Common LED AGL Failures
One failed LED darkens its whole string while the supply and driver stay healthy.
AGL Visual Encyclopedia: LED failure Driver failure Overheating
Tap a symptom to see the possible cause category.
Complete OFF
Possible Cause
- Driver or power failure
Dim
Possible Cause
- Current regulation issue
- Thermal issue
- LED degradation
Wrong colour
Possible Cause
- LED problem
- Optical problem
Flicker
Possible Cause
- Driver/control problem
Intermittent
Possible Cause
- Thermal, electrical or connector problem
Correct output, wrong direction
Possible Cause
- Alignment problem
Correct output, unacceptable beam
Possible Cause
- Optical problem
Troubleshooting LED AGL
Do not replace the LED first. A failed fixture may have healthy LEDs but a failed driver, failed surge protection, broken connector or control fault. Replacing the LED array without confirming the failure mechanism can waste time and create a second fault.
LED AGL Engineering Question Matrix
| Topic | Engineering Question |
|---|---|
| LED source | Is the semiconductor suitable? |
| Driver | Is current correctly regulated? |
| Thermal | Is junction temperature controlled? |
| Optics | Is the beam correctly formed? |
| Colour | Is the aviation colour correct? |
| Candela | Is intensity correct? |
| Coverage | Is the angular distribution correct? |
| Alignment | Is the fixture aimed correctly? |
| Power | Is the fixture compatible with its supply? |
| CCR | Is series-circuit operation correct? |
| Control | Are intensity and switching correct? |
| Monitoring | Can faults be detected? |
| Mechanical | Is the fixture physically suitable? |
| Environment | Can it withstand the site? |
| Certification | Is the correct qualification basis established? |
| Testing | Has actual performance been verified? |
LED Control Systems & ALCMS
Modern LED AGL systems can interface with the CCR, ALCMS, PLC, remote control, local control panels, monitoring systems and digital communication networks. FAA currently lists AC 150/5345-56B for L-890 Airport Lighting Control and Monitoring Systems. A modern LED fixture may allow more detailed monitoring than a simple ON/OFF circuit — fixture status, fault status, driver condition, communication, voltage, current and temperature, depending on the system.
"ON" is not the same as "healthy."
A fixture can report ON while still having incorrect alignment, reduced intensity, optical contamination, wrong colour or reduced beam coverage. Control feedback is not a substitute for field photometry.
Standards, Equipment Specification & Certification Framework
Choose the standard from the regulator first, then the contract, then the project.
AGL Visual Encyclopedia: Standard selection flowchart Standard comparison Applicable standard identification
AC 150/5345-46F, Specification for Runway, Taxiway, Heliport, and Vertiport Light Fixtures, is currently Active (issued September 30, 2024) and is the current FAA fixture specification for applicable light-fixture types.
AC 150/5345-53D, Airport Lighting Equipment Certification Program, is currently Active, with a September 2026 Addendum. FAA-approved third-party certifiers evaluate and certify airport-lighting equipment under this program.
AC 150/5345-26E covers L-823 plug and receptacle cable connectors; AC 150/5345-56B covers L-890 Airport Lighting Control and Monitoring Systems.
FAA Engineering Brief 67 (light sources other than incandescent/xenon) was historically important but is now listed as cancelled (dated March 2, 2016) — it should not be cited today as a current standalone FAA requirement.
| Layer | What It Governs |
|---|---|
| Facility / application requirements | How the airfield visual aid is arranged and used (FAA 150/5340 series) |
| Equipment requirements | How the fixture must perform (FAA 150/5345 series) |
| Certification | How equipment qualification is demonstrated under a particular program |
| Installation | How the equipment is actually installed at the airport |
| Operations | How the airport authorizes and uses the system |
Datasheet Review, Red Flags & Compliance Claims
Datasheet Review Checklist
- Input characteristics & rated power
- Operating current
- Intensity & colour data
- Beam pattern
- Temperature range
- Mounting details, dimensions, weight
- Protection rating
- Certification / qualification
- Maintenance information
Datasheet Red Flags
Be cautious when a datasheet only states "high brightness LED," "long life," "energy saving" or "FAA/ICAO compliant" without specifying the applicable standard, revision, test basis, photometric performance, equipment type or certificate/reference.
"FAA Compliant" Is Not a Complete Statement
A strong engineering statement identifies which FAA document, which revision, which equipment type, which test/qualification basis, and what certificate or listing applies — especially since FAA's equipment specifications and certification program are maintained separately.
"ICAO Compliant" Requires Context
Compliance for a particular installation can involve applicable Annex provisions, State regulations, airport requirements, equipment specifications, approved design, installation and operational approval. For Indian airport projects, this may involve ICAO, DGCA requirements, Airports Authority of India requirements, BIS/Indian Standards where applicable, tender specifications and manufacturer documentation — the governing project documents should always be identified.
Type Testing, FAT & SAT
Type Testing
Photometric, colour, electrical, environmental, thermal, mechanical, ingress protection, surge, EMC and endurance tests — the exact matrix depends on the applicable specification.
Factory Acceptance Testing (FAT)
Identification (model/serial/configuration), electrical input characteristics, optical intensity and colour, functional ON/OFF and dimming, mechanical housing and mounting, and documentation (certificates and test reports).
Site Acceptance Testing (SAT) verifies the installed system: fixture position, orientation, wiring, input, control, intensity, colour, beam distribution and overall system functionality.
Maintenance Strategy, Spares & Interchangeability
LED systems can reduce lamp replacement frequency, but maintenance does not disappear — it shifts toward electronics, driver, optics, connectors, seals, heat management, surge protection and alignment.
Spare Philosophy
LED systems require a different spare-parts philosophy from incandescent systems — complete fixture, driver, optical component, connector, surge-protection module, control module and sealing components. The recommended strategy depends on manufacturer architecture.
Interchangeability & OEM Configuration
Do not assume two fixtures with the same mounting size, power and colour are interchangeable — optical and electrical characteristics may differ. Changing OEM LEDs, driver, optics, PCB or surge protection can affect the basis on which equipment was tested or qualified.
LED Retrofit & Mixed-Technology Transition
Complete Fixture Replacement
Old fixture replaced by a new LED fixture.
Optical Retrofit
Existing housing receives a new optical assembly.
Lamp Replacement
Existing source is replaced inside an existing system.
These approaches are not technically equivalent — do not treat LED retrofit as a lamp change. An LED conversion may alter current waveform, power factor, heat distribution, spectrum, beam pattern, intensity, dimming and surge response. Before converting an existing fixture, assess optical geometry, thermal path, mechanical fit, driver compatibility, electrical input, certification basis, photometric performance and maintenance documentation.
Commissioning & Inspection Workflow
LED AGL Safety Principle
Do not assume that low power means low risk. The field system may still involve high-voltage series circuits, aircraft movement, pavement equipment, underground cable, electrical isolation transformers and control systems. Electrical and airside safety procedures remain essential.
LED vs Halogen Airfield Lights, Products, Retrofit, Maintenance & ALCMS Standards
LED against halogen on life, power, heat at the lens and purchase cost (indicative bars).
AGL Visual Encyclopedia: LED vs halogen Halogen to LED migration LED retrofit on a halogen series circuit
Practical points on choosing, retrofitting and maintaining LED airfield lighting.
LED vs halogen airfield lights
LED vs halogen airfield lights is mainly a trade of life, power use and maintenance against compatibility. LED fixtures usually use less power and need fewer lamp changes, but they have drivers and electronics that must work with the series circuit and CCR. Halogen fixtures are simple and proven but use more power and need regular lamp replacement. The right choice depends on the circuit, standard and maintenance plan.
LED airfield lighting products
LED airfield lighting products include edge, threshold, centreline, touchdown zone, approach and taxiway fixtures, signs and PAPI units. Each should be approved to the relevant standard, such as the FAA specifications referenced on this page, and be suitable for the circuit it will work on. Always check the manufacturer's datasheet and approval status before specifying.
LED airfield lighting retrofit
An LED airfield lighting retrofit replaces existing halogen fixtures with LED. Before starting, check CCR and transformer compatibility, the effect on circuit loading, photometric equivalence with the existing system, connector and mounting fit, and the impact on monitoring. A mixed LED and halogen circuit needs particular care, so plan the work in stages and test each stage.
LED airfield lighting maintenance
LED airfield lighting maintenance replaces most lamp-change work with inspection, cleaning, connector and seal checks, insulation testing and photometric checks. Failed LED units are usually replaced as modules, so spares and records matter. Light output falls slowly over time, so periodic checks are needed even when a fixture still lights.
LED airfield light maintenance
LED airfield light maintenance at fixture level means checking the lens for dirt and damage, the seal and gasket, the connector and the mounting, and confirming the light's output and colour are as expected. Replace damaged or failed units with approved equivalents, and record the change against the fixture.
ALCMS standards
ALCMS standards cover how airfield lighting control and monitoring systems should work and report, including their interface to lighting circuits. For LED lighting, the key point is compatibility, so the monitoring system correctly reads status, faults and brightness. Check the specification you follow, such as the FAA's ALCMS specification or ICAO guidance, against the edition in use.
Documentation & Design Checklist
LED AGL Documentation File
- Approved drawings
- Fixture datasheets
- Test certificates
- Certification documentation where applicable
- Photometric reports
- Electrical test reports
- Installation & alignment records
- Commissioning report
- Maintenance records
- Spare-parts documentation
Design Checklist
- Application — what visual aid is being designed?
- Photometry — required intensity, colour, beam pattern?
- Electrical — input and CCR/circuit compatibility?
- Thermal — maximum operating temperature?
- Mechanical — inset or elevated? What loads apply?
- Control — how is brightness controlled?
- Certification — what qualification basis applies?
LED AGL Quality Control
Verify supplied equipment
Check test documentation
Verify mounting and wiring
Verify operation
Verify photometry
LED AGL Commissioning Checklist
Click any item to mark it complete.
Application & Photometry
Electrical & Thermal
Mechanical & Control
Certification & Documentation
The Complete LED AGL Engineering Model
From the series circuit through the transformer and driver to the LED module, with heat carried away.
AGL Visual Encyclopedia: LED driver in a fixture LED driver LED module
LED semiconductor
Controlled electrical input
Heat removal
Beam formation
Mechanical/environmental protection
Power delivery
Brightness and switching
Position and alignment
Actual optical performance
Visual guidance function
LED changed the light source, not the responsibility of the AGL engineer. The engineer still has to verify colour, candela, coverage, configuration, electrical compatibility, thermal performance, mechanical integrity, control, monitoring, testing and documentation.
LED Troubleshooting Golden Rule: do not troubleshoot an LED AGL fixture by asking only whether the LED is glowing. Ask — is the correct amount of light being produced? In the correct colour? In the correct direction? At the correct intensity step? At the correct location? Under the required operating conditions? That is the real test of an airfield lighting system.
Precision AGL Academy takeaway: LED AGL is not simply a low-power replacement for incandescent lighting. It is an integrated aviation system where semiconductor technology meets optical engineering meets electrical engineering meets thermal engineering meets airfield geometry meets photometry meets operational safety. Do not ask only how efficiently an LED produces light — ask how accurately and reliably the complete fixture produces the right aviation visual cue where the pilot needs it.
Quick Knowledge Check
Q1. Why is candela more relevant than total lumens for airfield lighting?
Q2. What is the first troubleshooting mistake to avoid on a failed LED fixture?
Q3. Does an LED fixture eliminate the need for an isolation transformer on a conventional series circuit?
Q4. L70 refers to:
Q5. A fixture reports "ON" in the ALCMS. Does that confirm it is performing correctly?
Explore More AGL Engineering
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Verify the optical performance of the installed system.
Open AGL Photometry →Solar Airfield Ground Lighting
PV-battery-LED architecture for decentralized and off-grid lighting.
Open Solar AGL →Portable Airfield Ground Lighting
Temporary, emergency and rapid-deployment airfield lighting.
Open Portable AGL →Runway Lighting Systems
Edge, threshold, end and centreline lighting in the permanent system.
Open Runway Lighting →AGL Testing & Inspection
Electrical and photometric testing of LED fixtures.
Open Testing & Inspection →Taxiway Lighting Systems
LED fixtures deployed across the taxiway network.
Open Taxiway Lighting →Approach Lighting Systems
LED sources used within approach lighting configurations.
Open Approach Lighting →Right Colour. Right Intensity. Right Direction.
From LED source and driver design to thermal management, alignment and certification — explore the complete AGL knowledge base for LED, portable and solar lighting engineering.
Explore the AGL Engineering Knowledge Hub
Fundamentals
Standards & Compliance
Runway, Taxiway & Approach Lighting
Surface Movement & Safety
PAPI
Electrical Engineering & Power
Photometry & Testing
Maintenance, Inspection & Safety
Resources, Documentation & Careers
Frequently Asked Questions
Q1What is LED airfield ground lighting?
LED AGL uses semiconductor light sources instead of conventional incandescent lamps in aviation visual aids, including runway edge, threshold, end, centreline and touchdown-zone lights, taxiway lights, stop bars, runway guard lights, approach lights, PAPI, REIL, signs and obstruction lighting. The exact application depends on the equipment design and applicable standards.
Q2Is switching to LED just a lamp change?
No. An LED airfield light is a complete optical, electrical, thermal and mechanical system. An aviation-grade LED lighting system combines light source, optics, current or driver, thermal management, photometry, alignment, control, power, mechanical integrity and certification.
Q3What is the right question to ask about an LED fixture?
Not whether it is LED, but whether the complete LED fixture provides the required aviation performance for its intended function.
Q4How do LED and incandescent airfield lights differ?
LEDs use a semiconductor junction rather than a heated filament, are generally more efficient, generally longer-lived, switch and dim electronically depending on the driver, and depend on semiconductor and optics for colour rather than filters. Failure modes differ too: incandescent often fails by filament open circuit, while LED failures can include the driver, LED string or electronics.
Q5Do more lumens make a better airfield light?
No. Lumens describe total luminous flux, while candela describes luminous intensity in a direction. Airfield lighting is highly directional, so candela distribution is far more relevant than total lumens, and different fixtures such as a runway centreline and a taxiway edge light need different optical patterns.
Q6What are the Four Cs of LED AGL photometry?
Colour (is the aviation colour correct), Candela (is the intensity correct), Coverage (is the angular distribution correct) and Configuration (is the fixture installed correctly).
Q7What colours are used in aviation LED lighting?
Typical aviation colours are white, red, green, blue and yellow or amber, each tied to the visual-aid application. An LED should not be selected from a consumer colour designation such as cool white or warm white; the measured aviation colour performance is what matters.
Q8Can LED lights appear brighter than incandescent lights at the same intensity?
The page reports that FAA research found LED signal lights can appear brighter than incandescent signal lights at matched nominal luminous intensities, particularly for some aviation colours. This makes colour and brightness perception directly relevant to LED AGL engineering.
Q9If one LED in an array fails, does the light keep working?
A fixture may contain multiple LEDs, arrays, separate channels or redundant strings, and a multiple-LED array can allow output to be maintained even if one element fails. But this behaviour must be established from the product design and applicable test requirements.
Q10What is the FAA's position on LED migration according to this page?
The page notes that the FAA's January/February 2025 Safety Briefing described an ongoing LED migration program for airport lighting, highlighting LED PAPI and approach-lighting applications.
Engineering & Expert Notes
Verify Photometric Performance on the Actual Fixture
PhotometryData for the LED module does not guarantee the finished fixture meets requirements. Confirm type-approved performance.
Check Compatibility With the CCR and Series Circuit
CompatibilityLED loads differ from lamps. Confirm the electrical load and behaviour at all brightness steps.
Thermal Management Decides Lifespan
ThermalHeat shortens LED life. Check the mounting and the environment, especially for inset fixtures.
Colour Can Drift
ColourCheck chromaticity during commissioning and at intervals.
Plan Maintenance Differently
MaintenanceLEDs fail gradually and drivers can fail suddenly. Include both in the plan.
Rationalise Spares
SparesKeep modules and drivers appropriate to the installed types and review as products are updated.
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Important Notice, Disclaimer & Limitation of Liability
Please read before relying on any content on this page or on any record downloaded from it.
- Purpose and intended users. This page is an independent educational and informational reference for competent, suitably trained and authorised airfield ground lighting (AGL) and aerodrome personnel. It is not professional engineering, legal or regulatory advice, and using it creates no professional or client relationship. Learning-path and Academy references describe stages of learning only and are not a certification, accreditation or authorisation.
- Safety. Work on series circuits, constant current regulators (CCRs), isolating transformers, cables, connectors and lighting fixtures can be fatal. Always apply the aerodrome’s permit-to-work and isolation/LOTO procedures, prove dead, use correctly rated instruments and PPE, and follow the manufacturer’s instructions. Nothing here authorises work on live equipment or the bypassing of any safety device or interlock.
- Aviation operations. Nothing on this page authorises return to service, the installation, adjustment or modification of any aviation visual aid, a change of operating category (CAT I/II/III), a NOTAM or any aerodrome certification decision. These rest with the aerodrome operator, the air navigation service provider and the competent regulator.
- Standards, regulations and named sources. References to ICAO, FAA, EASA, DGCA, AAI, IEC, IEEE, ISO, BIS and other standards, regulations, AIP material and published sources, and statements about what a named airport, State or authority has published, are summaries for orientation as understood when the page was prepared. They are not official text, may be incomplete, amended or superseded, and have not been independently verified. Consult the current official editions, including the current AIP, AIRAC cycle and NOTAMs. Following this content does not guarantee compliance with any law, standard or approval, and official documents, regulations, the approved design and manufacturers’ instructions always prevail.
- Generic content; no warranty. Values, tolerances, intervals, sequences, examples, checklists and pass/fail or “compliant” wording are generic and indicative; real installations differ in design, make, model, age and condition. Content is provided “as is” and “as available”, without warranty of any kind, express or implied, including accuracy, completeness, currency or fitness for a particular purpose.
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