Runway Lighting
Rapid Exit Taxiway Indicator (RETIL) Light
Distance-to-go guidance to the next rapid-exit taxiway
RETILs show pilots the location of the next rapid-exit taxiway during rollout, in low-visibility and high-traffic runway operations. Precision AGL Solutions supplies RETIL solutions matched to rapid-exit layout, pattern, optics, circuit and approved project specification.
Supplied by Precision AGL Solutions
Product Overview
Rapid Exit Taxiway Indicator (RETIL) Light
What It Does
Rapid Exit Taxiway Indicator Lights, commonly known as RETILs, give pilots visual information about the location of the next available rapid-exit taxiway during the runway rollout.
They are installed on the runway surface in a dedicated pattern associated with the rapid-exit taxiway. The arrangement gives distance-to-go information and improves situational awareness, particularly where visibility is reduced and efficient runway exit matters operationally.
What We Supply
Precision AGL Solutions supplies and supports RETIL solutions selected according to:
- Rapid-exit taxiway layout and location
- Runway geometry and centreline lighting arrangement
- RVR / visibility conditions and traffic density
- RETIL pattern, fixture spacing and light colour
- Optical direction and photometric requirements
- Circuit configuration and control philosophy
- Pavement installation and project specification
The final arrangement should always follow the approved runway lighting layout and applicable aerodrome standard.
Primary Applications
Where RETIL Systems Are Used
Rapid-exit taxiwaysPre-exit location indication on the runway.
High-capacity runwaysSupports efficient runway exit.
Heavy-traffic runwaysReduced runway occupancy-time strategies.
Low-visibility operationsExit guidance when visibility is reduced.
Precision approach runwaysComplements the runway visual aid environment.
Rehabilitation projectsRunway rehabilitation and AGL modernisation.
Capacity improvementAirport capacity improvement projects.
ICAO Annex 14 recommends RETILs on runways intended for use in RVR below 350 m and/or where traffic density is heavy. Confirm the figure against your edition.
Function of RETIL Lighting
Telling the Pilot Where the Exit Is, While Still Rolling Out
What the Lights Do
RETILs indicate the location of the next rapid-exit taxiway while the aircraft is still on the runway. This improves situational awareness so the pilot can:
- Identify the upcoming rapid-exit taxiway
- Estimate distance to the exit
- Maintain an appropriate rollout strategy
- Concentrate on runway centreline alignment
- Apply braking and deceleration at an appropriate stage
- Prepare for the turn onto the rapid-exit taxiway
Low-Visibility Value
In low-visibility conditions RETILs provide useful situational-awareness information while allowing the pilot to remain focused on runway centreline tracking.
They supplement, rather than replace, runway centreline lighting: centreline lights give longitudinal alignment, RETILs give upcoming exit location and distance.
RETIL Visual Pattern
The 3-2-1 Sequence
RETILs use a distinctive pattern rather than a continuous line of lights. Under the ICAO arrangement the sequence gives progressive distance information toward the rapid exit: groups of 3, 2 and 1 lights at approximately 100 m intervals from the associated exit reference, per the applicable layout. A complete RETIL set is six lights (3 + 2 + 1). The Annex 14 figure places the groups at 300 m, 200 m and 100 m before the rapid-exit taxiway point of tangency, so the last single light sits about 100 m from it. The exact positioning must be taken from the approved project drawing.
RETIL Pattern — Schematic
Location of RETILs
Same Side as the Associated Rapid Exit
Positioning
RETILs are installed on the same side of the runway centreline as the associated rapid-exit taxiway. The applicable ICAO figure relates the runway centreline, RETIL set, light spacing, rapid-exit taxiway and point of tangency.
ICAO provisions specify lights spaced 2 m apart, with the light nearest the runway centreline displaced 2 m from the centreline.
Multiple Rapid-Exit Taxiways
Where a runway has more than one rapid exit, RETIL patterns must be arranged so the indication for one exit does not overlap that for another. Layout review should consider:
- Exit-to-exit separation
- RETIL pattern visibility and overlap
- Runway length
- Point of tangency
- Runway centreline
- Adjacent exit geometry
Light Colour & Operation
Fixed, Unidirectional, Yellow
Colour & Direction
ICAO specifies RETILs as fixed, unidirectional yellow lights, aligned to be visible to the pilot of a landing aircraft in the direction of approach. Evaluate fixtures for:
- Yellow colour and chromaticity
- Unidirectional output
- Beam distribution and intensity
- Optical direction
- Visibility from the landing direction
Not a Flashing Warning Light
RETILs are fundamentally different from Runway Guard Lights, REIL systems and flashing runway warning lights. They are specified as fixed lights, not an alternating flashing warning system.
This distinction matters for product classification and technical procurement.
Product Comparison
Keep RETIL Distinct from Similar Products
RETIL vs Runway Guard Light
| Feature | RETIL | Runway Guard Light |
|---|---|---|
| Primary purpose | Rapid-exit location / distance indication | Runway-entry warning |
| Typical colour | Yellow | Yellow |
| Operation | Fixed | Alternating / flashing |
| Installation | Runway surface | Elevated or inset |
| Direction | Unidirectional | Unidirectional |
| Location | Before associated rapid exit | Runway holding position |
| Typical pattern | 3-2-1 RETIL pattern | Pair / row of alternating lights |
RETIL vs Runway Centreline Light
| Feature | RETIL | Runway Centreline Light |
|---|---|---|
| Primary purpose | Rapid-exit identification | Runway longitudinal guidance |
| Typical colour | Yellow | White / applicable centreline sequence |
| Operation | Fixed | Fixed |
| Layout | Distinctive 3-2-1 pattern | Continuous centreline layout |
| Location | Adjacent to centreline on exit side | Runway centreline |
| Information | Distance / location of next rapid exit | Aircraft alignment |
RETIL vs Rapid-Exit Taxiway Centreline Light
| Feature | RETIL | Rapid-Exit Taxiway Centreline Light |
|---|---|---|
| Location | Runway surface before exit | Exit taxiway route |
| Function | Indicates upcoming exit | Guides aircraft through exit |
| Typical ICAO colour | Yellow | Green; alternating green and yellow within the ILS/MLS critical/sensitive area |
| Pattern | 3-2-1 | Centreline sequence |
| System role | Pre-exit guidance | Turn / route guidance |
A rapid-exit taxiway may use both RETIL and taxiway centreline lighting as part of the complete runway-exit guidance arrangement.
Optical & Photometric Performance
RETILs Are Precision Visual-Aid Equipment
| Parameter | Engineering Requirement |
|---|---|
| Light source | LED / approved technology |
| Colour | Yellow |
| Direction | Unidirectional |
| Operation | Fixed |
| Intensity | Standard / project specific |
| Horizontal / vertical coverage | Applicable requirement |
| Beam distribution | Fixture-specific |
| Optical axis | Critical |
| Chromaticity | Applicable standard |
| Pattern visibility | Critical |
| Photometric verification | Project dependent |
ICAO inspection guidance requires RETIL intensity and distribution to conform to the standards associated with the runway centreline-light spacing arrangement. The optical system should give sufficient cockpit visibility while avoiding unnecessary light outside the intended viewing sector.
LED Light Source
LED Technology
Potential Advantages
- Long operating life
- Reduced lamp replacement
- Low routine maintenance
- Consistent yellow output
- Stable optical performance
- Controlled beam distribution
- Improved energy efficiency
- Compatibility with modern AGL systems
Evaluate the Whole Fixture
A fixture should nevertheless be assessed on complete photometric, electrical, mechanical and environmental performance, not on the light source alone.
Electrical Characteristics
Coordinate with the Runway Lighting System
Parameters to Verify
- Operating current
- Series-circuit characteristics
- Transformer rating
- Power consumption
- Connector arrangement
- Secondary cable
- Circuit monitoring
- Control requirements
Separate Circuit Arrangement
ICAO inspection guidance identifies provision for RETILs to be supplied from a separate circuit from other runway lighting so they can be used when other runway lighting is switched off. Where this applies, verify:
- Dedicated circuit and CCR arrangement
- Circuit protection and switching
- Monitoring
- Transformer loading
- Control-system integration
Constant Current RegulatorSeries supply
Primary AGL CircuitSeries loop
Isolating TransformerFixture isolation
Secondary CableTo fixture
RETIL FixtureYellow output
The actual arrangement depends on the airport lighting system.
Pattern Integrity
Do Not Display an Incomplete Pattern
ICAO Provision
The RETIL pattern should not be displayed when a lamp failure or other failure prevents the full prescribed pattern from being shown. The aim is to avoid presenting an incomplete or misleading indication.
Design & Control Considerations
- Individual lamp failure
- Circuit failure
- Pattern integrity
- Fault monitoring
- Inhibit logic
- Maintenance indication
Mechanical Construction & Pavement Installation
Runway-Surface Fixtures Need Pavement Coordination
Typical Construction
Depending on manufacturer and configuration:
- In-pavement fixture body
- Optical lens and yellow optical assembly
- LED module
- Reflector / optical system
- Load-bearing housing
- Gasket and sealing system
- Mounting hardware
- Secondary cable connection
- Drainage provisions
Confirm materials, dimensions and construction from current manufacturer documentation.
Pavement Checks
- Housing: dimensions, load-bearing design, fixture compatibility, installation depth
- Pavement: cut-out, concrete/asphalt interface, seating, finished level, drainage, sealing
- Optical alignment: light direction, beam axis, orientation, position relative to centreline
Installation Accuracy
The Pattern Depends on Exact Location
- 2 m spacing between lights within each set
- 2 m offset of nearest light from the runway centreline
- Correct side of runway
- Correct longitudinal position
- Correct relationship to the rapid-exit taxiway
- No overlap between adjacent exit patterns
The applicable project drawing controls final setting-out dimensions.
System Integration
RETIL in the Runway-Exit Guidance Sequence
Runway Centreline Guidance → RETIL Exit Indication → Rapid-Exit Turn → Rapid-Exit Taxiway Centreline → Taxiway Network
Design should consider RVR, traffic density, rapid-exit availability, aircraft operating characteristics, runway occupancy objectives, existing centreline lighting, ambient background lighting and adjacent exit geometry, so that RETILs give useful distance information without ambiguity with other runway visual aids. Once the aircraft begins turning onto the exit, taxiway centreline lighting becomes the principal route guidance.
Commissioning & Testing
Verify the Complete Visual Pattern, Not Only Individual Lamps
Visual Inspection
- Fixture and lens condition
- Yellow colour
- Location, pattern and spacing
- Centreline offset
- Optical orientation
- Pavement interface and housing
- Cable, connector, moisture evidence
Electrical Tests
Per approved procedure:
- Circuit continuity
- Insulation resistance
- Transformer verification
- Secondary connection
- CCR operation and circuit current
- Monitoring
Pattern & Photometric
- Full 3-2-1 pattern and sequence
- Longitudinal and lateral position
- No overlap with another RETIL set
- Visible from landing direction
- Where required: colour, intensity, beam direction and distribution
Inspection & Maintenance
Routine Inspection
Optical
- Lens cleanliness
- Lens damage
- Yellow output
- Intensity
- Beam direction
Mechanical
- Fixture seating
- Housing
- Fasteners
- Pavement interface
- Physical damage
Electrical
- Transformer
- Cable and connector
- Circuit current
- Insulation
- Moisture
Pattern
- Complete 3-2-1 pattern
- Correct spacing
- No missing indication
- Correct alignment
- No overlap with other exits
Common Failure Modes
What Goes Wrong
One RETIL Light Off
- LED / light-source failure
- Secondary cable fault
- Connector problem
- Transformer fault
- Fixture internal failure
Complete Pattern Off
- CCR / circuit failure
- Primary cable fault
- Control-system failure
- Transformer / circuit failure
- Pattern-inhibit logic
Incomplete Pattern
- Individual lamp failure
- Wiring fault
- Connector failure
- Incorrect circuit arrangement
- Control-system configuration
Incorrect Position
- Survey / set-out error
- Incorrect runway reference
- Pavement reconstruction
- Fixture relocation
- Misread approved layout
Poor Visibility
- Optical contamination
- Incorrect beam orientation
- Low intensity
- Damaged optical system
- Incorrect fixture type
- Ambient-light conditions
A complete pattern matters: an incomplete RETIL display may not give the intended distance information.
Engineering Troubleshooting Sequence
Work from Control to Pattern
RETIL Control
CCR / Dedicated Circuit
Primary Series Circuit
Isolating Transformer
Secondary Cable
RETIL Fixture
Light Source
Optical Alignment
Pattern & Photometry
Pattern-level: Exit location → runway centreline → 2 m spacing → 2 m centreline offset → 100 m pattern spacing → overlap with other exits
Product Selection Matrix
Selection Parameters
| Selection Parameter | Requirement |
|---|---|
| Application | Rapid-exit taxiway indication |
| Runway / RVR / traffic density | Project specific |
| Pattern | 3-2-1 / applicable configuration |
| Light colour | Yellow |
| Direction / operation | Unidirectional / fixed |
| Spacing within each set | 2 m |
| Centreline offset | 2 m |
| Longitudinal arrangement | Project / standard specific |
| Intensity & beam distribution | Standard / fixture specific |
| Installation | Inset / runway surface |
| Housing | Load-bearing |
| Circuit | Project specific / dedicated where applicable |
| Transformer | Matching equipment |
| Control & monitoring | Project specific |
| Documentation | TDS / photometry / certificates |
Product Selection Checklist
Before Ordering, Confirm
- Airport / project
- Runway identification
- Rapid-exit taxiway identification
- Runway length
- Runway centreline lighting spacing
- RVR requirement
- Traffic-density requirement
- RETIL requirement and pattern
- Number of RETIL sets
- Same-side arrangement
- 2 m light spacing
- 2 m centreline offset
- Longitudinal positioning
- No overlap with other RETIL patterns
- Yellow light
- Unidirectional output
- Fixed operation
- Optical direction
- Intensity and beam distribution
- LED / approved light source
- Series-circuit arrangement
- Dedicated circuit where required
- Isolating transformer
- Connector type
- Housing and installation depth
- Pavement cut-out and drainage
- Monitoring
- Environmental requirements
- Applicable standard
- Manufacturer TDS
- Photometric documentation
- Compliance / type-test documentation
- Project approval requirements
Technical Submittal
Technical Documents to Request
For technical evaluation and procurement, request:
- Product datasheet
- Technical specification
- Photometric data
- Beam distribution diagram
- Yellow colour / chromaticity information
- RETIL pattern drawing
- Fixture spacing requirements
- Optical-direction information
- Electrical specification
- Rated operating current
- Power consumption
- Transformer requirement
- Connector details
- Housing drawing
- Fixture dimensions
- Installation depth
- Pavement cut-out details
- Mounting details
- Drainage requirements
- Circuit diagram
- Control / interface information
- Monitoring / fault information
- Weight
- Material specification
- Environmental rating
- Installation manual
- Maintenance manual
- Compliance certificates
- Type-test reports
- Warranty information
Standards & References
Governing Standards
Design, select, install and test against the applicable edition of the governing aerodrome standard and approved project specification.
ICAO
Annex 14 — Aerodromes, Volume I (9th Edition, July 2022, with Amendment 18 at the time of writing), Chapter 5 (rapid exit taxiway indicator lights) establishes the principal characteristics:
- Application to low-RVR / heavy-traffic runways
- Prescribed 3-2-1 pattern at 100 m intervals before the rapid-exit taxiway point of tangency
- Same side of centreline as the rapid exit
- 2 m spacing; nearest light 2 m from centreline
- No overlap between different rapid exits
- Fixed unidirectional yellow lights, visible in landing direction
Colour and photometric requirements sit in Annex 14 Appendices 1 and 2. Section numbers change between editions, so check the clause against your copy. Doc 9157 Part 4 (Visual Aids) and Part 5 (Electrical Systems) give design guidance.
Guidance also addresses separate-circuit supply.
FAA
FAA practice does not use RETIL as a direct equivalent. Runway exits are lit with taxiway centreline lead-off lights under AC 150/5340-30J, and distance-to-go information is given by runway distance-remaining signs (AC 150/5340-18H).
On an FAA project, verify whether the design calls for RETILs, rapid-exit taxiway centreline lighting or another FAA-approved arrangement.
India
For Indian airport projects also verify:
- DGCA requirements
- Airport-specific AGL specifications
- Approved rapid-exit taxiway layout
- Centreline-light spacing and RVR / low-visibility procedures
- Project BOQ and Employer's requirements
- Applicable Indian Standards and airport operator requirements
Always verify the applicable document edition and project-specific requirements before procurement, technical approval or installation.
FAQ
Rapid Exit Taxiway Indicator (RETIL) Light — Frequently Asked Questions
What is a rapid exit taxiway indicator light (RETIL)?
RETILs give pilots visual information about the location of the next available rapid-exit taxiway during the runway rollout. They are installed on the runway surface in a dedicated pattern associated with the rapid-exit taxiway, give distance-to-go information and improve situational awareness, particularly where visibility is reduced.
What is the RETIL 3-2-1 pattern?
The ICAO arrangement uses groups of 3, 2 and 1 lights at approximately 100 m intervals before the rapid exit, so a complete RETIL set is six lights. The Annex 14 figure places the groups 300 m, 200 m and 100 m before the rapid-exit taxiway point of tangency, so the last single light sits about 100 m from it. Take the exact positions from the approved project drawing.
Where are RETILs installed relative to the runway centreline?
RETILs are installed on the same side of the runway centreline as the associated rapid-exit taxiway. ICAO provisions specify lights spaced 2 m apart, with the light nearest the runway centreline displaced 2 m from the centreline. Where a runway has more than one rapid exit, the patterns must be arranged so that the indication for one exit does not overlap another.
What colour and mode of operation do RETILs use?
ICAO specifies RETILs as fixed, unidirectional yellow lights, aligned to be visible to the pilot of a landing aircraft in the direction of approach. They are fixed lights, not a flashing warning system.
When does ICAO recommend RETILs?
ICAO Annex 14 recommends RETILs on runways intended for use in RVR below 350 m and/or where traffic density is heavy. Confirm the figure against your edition of the standard.
How does a RETIL differ from a runway guard light or a runway centreline light?
A RETIL is a fixed yellow light indicating the location and distance of the next rapid exit, while a runway guard light is an alternating or flashing runway-entry warning at a holding position. RETILs supplement rather than replace runway centreline lighting: centreline lights give longitudinal alignment, and RETILs give upcoming exit location and distance. Once the aircraft turns onto the exit, taxiway centreline lighting becomes the principal route guidance.
Do RETILs need a separate circuit?
ICAO inspection guidance identifies provision for RETILs to be supplied from a separate circuit from other runway lighting, so that they can be used when other runway lighting is switched off. Where this applies, verify the dedicated circuit and CCR arrangement, circuit protection and switching, monitoring, transformer loading and control-system integration.
What happens if one RETIL light fails?
ICAO provides that the RETIL pattern should not be displayed when a lamp failure or other failure prevents the full prescribed pattern from being shown, to avoid presenting an incomplete or misleading indication. Design and control considerations include fault monitoring, inhibit logic and maintenance indication.
Does the FAA use RETILs?
FAA practice does not use RETIL as a direct equivalent. Runway exits are lit with taxiway centreline lead-off lights under AC 150/5340-30J, and distance-to-go information is given by runway distance-remaining signs under AC 150/5340-18H. On an FAA project, verify whether the design calls for RETILs, rapid-exit taxiway centreline lighting or another FAA-approved arrangement.
What are the common faults in a RETIL installation?
One light off usually points to an LED or light-source failure, a secondary cable fault, a connector problem, a transformer fault or an internal fixture failure. A complete pattern off points to the CCR or circuit, primary cable, control system or pattern-inhibit logic. An incomplete pattern, an incorrect position from a set-out error or pavement reconstruction, and poor visibility from contamination or beam orientation are also common. Troubleshoot from control to pattern.
What should be confirmed before ordering RETIL lights?
Confirm the runway and rapid-exit taxiway identification, runway length, centreline-light spacing, RVR and traffic-density requirement, the RETIL pattern and number of sets, same-side arrangement, 2 m spacing and 2 m centreline offset, and fixed, unidirectional yellow output. Also confirm the series-circuit arrangement and any dedicated circuit, isolating transformer, connector type, housing and installation depth, pavement cut-out and drainage, monitoring, and the datasheet, photometric and compliance documentation.
Why Precision AGL Solutions
A Complete-System Approach
We treat RETILs as part of the complete runway-exit visual guidance system, so selection is coordinated with both the runway lighting and the rapid-exit taxiway layout.
Runway Geometry → Rapid Exit Location → RETIL Pattern → Centreline Guidance → Optical Configuration → Housing → Transformer → Series Circuit → Control → Photometry → Maintenance
Procurement Information for Indian Projects
Indian public tenders commonly ask for the documents below. State which ones your tender requires when you send the enquiry, so they are covered in the quotation.
- Manufacturer / OEM authorisation
- Country of origin and local-content declaration (for Make in India purchase preference)
- Type-test and routine-test certificates, and the FAA / ICAO / IEC compliance documents named in the specification
- Datasheets, drawings and installation instructions
- Warranty, delivery period and spares support
- GeM catalogue or tender-portal requirements, where applicable
Planning a Rapid-Exit or Low-Visibility Lighting Project?
Submit your runway layout, rapid-exit taxiway layout, runway length, centreline-light spacing, RVR requirement, traffic-density information, existing RETIL arrangement, approved lighting layout, BOQ or technical specification. We can review the runway-exit configuration and support selection of the RETIL arrangement, optical characteristics, circuit interface and supporting documentation.
- Emailprecisionaglsolutions@gmail.com
- Websiterahulsharmaagl.in
- LinkedInPrecision AGL Solutions
- Phone+91 98214 96412
Engineering Note
RETILs are a specialised runway visual aid intended to provide distance-to-go information for a rapid-exit taxiway. Their effectiveness depends on the complete relationship between runway geometry, RETIL pattern, fixture spacing, 2 m centreline offset, yellow optical output, landing-direction visibility, circuit reliability and rapid-exit taxiway location.
For projects using FAA standards, do not automatically treat an ICAO RETIL configuration as an FAA-equivalent product. Verify the project-specific FAA visual-aid design and approved fixture requirements before procurement.
Product Disclaimer
Product availability, configuration, dimensions, electrical characteristics, photometric performance, certifications and compliance status depend on the selected manufacturer and project specification. The technical values published on this page should not be treated as a substitute for the manufacturer's current approved Technical Data Sheet.
Final selection shall be based on the approved project specification, applicable aviation standards, authority requirements, manufacturer documentation and site conditions. Use of this page is also subject to the Legal Notice, Disclaimer & Terms of Use.
Standards and editions referenced on this site are listed on the Standards Reference page.