Airfield Signs
Back Lit Airfield Sign Boards for Movement Areas
Clear, consistent legend visibility during night-time airport operations
Back-lit sign boards provide illumination from behind the sign face, configured for dimensions, legend, illumination system, mounting and environmental protection to suit your airport layout and project requirements.
Supplied by Precision AGL Solutions
Product Overview
Back Lit Airfield Sign Boards
What It Is
Back-lit sign boards provide illumination from behind the sign face and suit a wide range of airfield guidance applications. The rear arrangement gives clear, consistent visibility of the approved legend during night-time operations.
Precision AGL Solutions supplies them for taxiways, aprons, runway-holding positions and aircraft stand guidance. Dimensions, legend, illumination system, mounting and environmental protection follow the airport layout and project requirements.
Typical Assembly
- Sign face and approved legend
- Internal illumination system, LED or other specified source
- Reflective or optical internal surfaces
- Sign enclosure, electrical connection arrangement
- Mounting supports with frangible or breakaway components
- Weather and environmental protection
Applications
Configured for Each Airfield Function
Taxiway signsTaxiway identification and directional guidance, location signs.
Holding positionsRunway-holding positions, intermediate holding positions and movement-area intersections.
Apron guidanceApron guidance and aircraft stand identification.
Gate & stand areasGate and stand area signage.
ReplacementReplacement of existing illuminated signs.
ProjectsAirport infrastructure projects, new construction and expansion.
Coordinate the sign layout with the approved airport signage plan, pavement markings and associated airfield lighting.
Sign Categories & Colours
Colour Follows the Sign Category
| Sign category | Legend / background (ICAO Annex 14, FAA) | Typical use |
|---|---|---|
| Mandatory instruction | White legend on red background | Runway designation, CAT I/II/III holding positions, runway-holding position, no-entry |
| Location | Yellow legend on black background (yellow border where required) | Identifies the taxiway or runway the aircraft is on |
| Direction | Black legend on yellow background | Identifies the taxiway to turn onto and its direction |
| Information | Black legend on yellow background | Operational information such as stand or apron routing, as set by the authority |
Why It Matters
- Colours are fixed by sign category, not chosen per project
- Red is reserved for mandatory instruction signs
- Each sign face must meet the chromaticity and luminance limits for its colour
- Rear illumination must light legend and background evenly so colours read correctly at night
- A location sign is normally provided together with direction signs, and with runway designation signs except at runway/runway intersections; confirm the pairing in Annex 14 Chapter 5
Engineering Note
Colour, legend style and character form come from the applicable standard and the airport signage plan. Confirm them in the approved sign schedule before fabrication.
Back-Lit Illumination
Light Source Behind the Sign Face
What It Provides
- Even illumination of the legend, clear visual identification
- Controlled light distribution, good night-time visibility
- Consistent appearance across the sign face
- Suitable integration with modern LED systems
Design Principle
Under ICAO Annex 14, signs are to be illuminated for night use on instrument runways and on non-instrument runways of code number 3 or 4, and when used in runway visual range below 800 m. Otherwise a retroreflective sign may be acceptable where the authority permits. Sign luminance should follow the airfield brightness steps. The source sits behind the face rather than at the panel edge. Design the internal optics as part of the complete sign assembly to minimize localized bright areas and dark zones.
LED Illumination
Efficient Light Source for Modern Signs
Potential Advantages
- Efficient operation, long operating life
- Reduced routine light-source replacement
- Stable illumination, fast switching
- Low maintenance, compatibility with modern controls
Selection
Select LED modules, drivers and electrical components to suit the sign dimensions and project electrical architecture.
Sign Legend
Established From the Approved Signage Schedule
Legend May Display
- Taxiway and location identifiers, directional arrows
- Holding-position information
- Stand numbers, gate identifiers, apron information
- Operational symbols, combined text and graphics
Character Configuration
Determine character height, spacing and overall legend configuration from the required viewing distance and applicable project criteria.
Sign Dimensions
Determined by Legend and Character Configuration
Dimensional Considerations
- Overall length, height and enclosure depth
- Character height, number of characters, arrow dimensions
- Legend spacing, internal illumination clearance
- Mounting-point locations, cable-entry position
Principle
Larger signs may need additional support or structural provisions. Establish final dimensions from the approved sign schedule and installation location.
Luminance & Uniformity
Readable Without Glare
Luminance
The illuminated legend should stay clearly visible under expected operating conditions, with no excessive glare or localized brightness.
Uniformity
- Prevents bright spots and dark areas
- Avoids uneven character appearance
- Maintains readability, avoids visual distraction
- Verify against project specification and current signage requirements
Internal Illumination Arrangement
Matched to the Sign Size
Design Considerations
- LED position, number of light modules
- Internal reflective surfaces, light distribution
- Sign-face transmission characteristics
- Enclosure depth, heat management, maintenance access
Principle
Match the illumination system to the sign dimensions rather than using the same light-source configuration for every sign size.
Construction & Materials
Built for Continuous Outdoor Exposure
Construction May Include
- Corrosion-resistant materials, durable sign faces
- Protective coatings, sealed enclosures
- Weather-resistant electrical components
- Protected cable entries, robust mounting hardware
- Suitable internal optical materials
Material Selection
Account for rain, dust, UV, temperature variation, wind and cleaning activity, based on the airport environment and expected service conditions.
Mounting & Frangibility
Support and Clearance
Possible Arrangements
- Ground-mounted supports, dedicated sign posts
- Base-mounted assemblies, adjustable supports
- Frangible or breakaway supports
- Project-specific structural arrangements
Safety
Mounting must be stable while maintaining required aircraft and vehicle clearances. Signs on the movement area must be frangible and low enough to clear aircraft propellers and engine pods. Confirm sign height, distance from the pavement edge and the frangible point in the airfield safety and clearance assessment.
Electrical Configuration
Engineered for the Airport Infrastructure
Parameters to Confirm
- Series or parallel circuit, transformer rating, rated power, current
- LED driver configuration, cable connection
- Switching, dimming, control interface
- Surge protection, earthing/grounding
Control Integration
Airfield signs normally run on a series circuit (constant current, through an isolating transformer) or a parallel circuit (constant voltage). The LED driver must suit the transformer secondary or supply voltage and respond correctly to the regulator brightness steps. Confirm the electrical interface before procurement.
Environmental Protection
Designed for Continuous Outdoor Operation
Considerations
- Rain and moisture, dust, UV exposure
- Temperature variation, condensation
- Wind loading, corrosion
- Cleaning and maintenance, internal moisture protection
Verification
Establish the required enclosure and ingress protection from the installation environment and project specification.
Technical Data
Typical Project Considerations
| Parameter | Typical Project Consideration |
|---|---|
| Product type | Back-lit airfield sign board |
| FAA sign types (L-858) | L-858R mandatory instruction; L-858Y direction, destination and information; L-858L location (confirm size, style and class per AC 150/5345-44L) |
| Sign dimensions | Project-specific |
| Legend | Taxiway, location, direction, holding position, apron or stand information |
| Character configuration | Project-specific |
| Character height | According to viewing distance and signage requirements |
| Light source | LED or specified illumination technology |
| Illumination | Internal/rear illumination |
| Luminance | Project-specific |
| Optical uniformity | Controlled across sign face |
| Sign enclosure | Outdoor airfield-rated construction |
| Input power | Project-specific |
| Electrical interface | According to project lighting/signage system |
| Mounting | Ground-mounted or project-specific |
| Frangibility | Where required |
| Environmental protection | Project-specific |
| Cable entry | Project-specific |
| Control | Local or integrated control, where applicable |
Final technical values should be confirmed against the selected sign configuration and project requirements.
Back-Lit Sign Selection
Begin With the Application
ApplicationTaxiway, location, direction, holding position, apron, stand, gate
LegendExact approved characters, numbers, arrows, symbols
Character heightPer viewing distance and criteria
DimensionsLegend, spacing, illumination performance
IlluminationLight source, luminance, uniformity
MountingSurface, space, clearance, frangibility
ElectricalPower, driver, cable, control interface
Installation
Verify Before Installation
Key Considerations
- Approved location, viewing direction, aircraft clearance
- Taxiway and apron geometry, pavement markings
- Foundation, support arrangement, frangibility
- Cable routing, electrical connection, drainage
- Accessibility for maintenance
Principle
The sign must stay visible from the intended direction and not be obstructed by aircraft, vehicles, structures or other equipment.
Coordination With Airfield Lighting
Part of the Wider Visual Guidance System
Coordinate With
- Taxiway centreline and edge lights
- Runway guard lights, stop bars
- Holding-position, taxiway and apron markings
- Stand guidance systems, other illuminated signs
Purpose
Review sign location, orientation and illumination as part of the overall airfield layout.
Commissioning
Inspect Against Project Documentation
InspectPhysical inspection, mounting and support
ElectricalConnection checks
IlluminationTesting, legend visibility
PhotometricLuminance and uniformity where required
ControlSwitching verification
Night checkOrientation, night-time visual inspection
RecordFinal installation details
Coordinate with the wider airport lighting and signage acceptance process where applicable.
Maintenance
Periodic Inspection Remains Necessary
Activities
- Cleaning the sign face, checking for physical damage
- Inspecting mounting hardware, cable entries, electrical connections
- Checking LED modules and drivers, uneven illumination
- Inspecting for moisture ingress, legend condition, sign colour and luminance, corrosion or coating deterioration
Principle
LED systems reduce routine light-source replacement, but the complete sign assembly should still be periodically inspected.
Common Problems
Typical Problems and Causes
| Problem | Possible Causes / Notes |
|---|---|
| Uneven illumination | LED or optical component problems, contamination, internal deterioration, component failure |
| Reduced luminance | LED degradation, driver faults, electrical supply problems, contaminated sign face |
| Moisture ingress | Damaged seals, cable-entry problems, enclosure deterioration |
| Damaged sign face | Impact or deterioration reduces legend clarity; assess promptly |
| Support damage | Loose, bent, corroded or damaged mounting components; inspect and repair |
Replacement & Retrofit
Modernizing Ageing Illumination Systems
Applications
- Replacement of damaged signs, LED conversion
- Airport signage modernization, standardization
- Taxiway rehabilitation, apron expansion
- Stand redevelopment, ageing illumination systems
Before Procurement
Check existing foundations, support arrangements, cable routes and electrical interfaces before selecting the replacement unit.
Procurement Checklist
When Requesting a Back-Lit Sign Board, Provide
Sign Details
- Airport/project name, sign type
- Approved legend, character height, number of characters
- Arrow or symbol requirements
- Required dimensions, installation location
- Mounting arrangement, frangibility requirements
System & Documentation
- Illumination requirements
- Electrical supply, control requirements
- Environmental conditions
- Applicable project standards
- Required documentation
Safety
Electrical Safety — Isolation and Lock-Out
WARNING — never open a live series circuit. An open series circuit driven by a constant-current regulator can produce dangerously high voltage. Opening, cutting or disconnecting any part of an energised circuit can cause serious injury or death and damage equipment.
- De-energise the circuit at the regulator and apply the site lock-out / tag-out (LOTO) procedure before any work
- Where the circuit must be isolated or shorted, use the series circuit cut-out switch or approved isolation device — not an improvised bypass
- Verify the circuit is de-energised and the output is isolated before touching conductors, connectors, splices or transformers
- Work only under the airport's permit-to-work system, using qualified personnel and the manufacturer's instructions
- Follow the applicable national electrical safety regulations and site procedures
Standards & Project Compliance
Verify the Applicable Edition
Relevant References
- ICAO Annex 14 Vol. I (Chapter 5, signs; Appendix 1, colours; Appendix 4, taxiing guidance sign design)
- ICAO Doc 9157 Aerodrome Design Manual, Part 4
- FAA AC 150/5345-44L (runway and taxiway signs) and AC 150/5340-18H (sign standards)
- DGCA India CAR Section 4 and applicable national requirements
- Airport-specific signage specifications
- Project airfield lighting requirements, approved signage schedules and layout drawings
Principle
Select and design signage to the applicable airport requirements. Confirm the applicable standard and edition for each project before final technical approval.
Documentation & Support
Practical Focus on Application and Integration
Documentation
- Datasheets, technical specifications, sign schedules
- General arrangement drawings, mounting details
- Electrical information, installation instructions
- Maintenance, inspection and commissioning information
Why Precision AGL Solutions
Support covers sign configuration, legend and character selection, illumination arrangement, luminance requirements, mounting assessment, electrical interface review, retrofit evaluation and procurement support.
FAQ
Back Lit Airfield Sign Boards — Frequently Asked Questions
What are back-lit airfield sign boards?
Back-lit sign boards provide illumination from behind the sign face and suit a wide range of airfield guidance applications, including taxiways, aprons, runway-holding positions and aircraft stand guidance. The rear arrangement gives clear, consistent visibility of the approved legend at night. A typical assembly has the sign face and approved legend, an internal illumination system, reflective or optical internal surfaces, an enclosure, and mounting supports with frangible or breakaway components.
What colours do the different sign categories use?
Mandatory instruction signs use a white legend on a red background, location signs a yellow legend on black (with a yellow border where required), and direction and information signs a black legend on yellow. Colours are fixed by sign category, not chosen per project, and red is reserved for mandatory instruction signs. The FAA types are L-858R for mandatory instruction, L-858Y for direction, destination and information, and L-858L for location, with size, style and class confirmed per AC 150/5345-44L.
When must airfield signs be illuminated?
Under ICAO Annex 14, signs are to be illuminated for night use on instrument runways and on non-instrument runways of code number 3 or 4, and when used in runway visual range below 800 m. Otherwise a retroreflective sign may be acceptable where the authority permits. Sign luminance should follow the airfield brightness steps.
How does back-lit illumination work, and why use LEDs?
The light source sits behind the sign face rather than at the panel edge, giving even illumination of the legend and background so colours read correctly at night. The internal optics should be designed as part of the complete sign assembly to minimise localised bright areas and dark zones, and matched to the sign size rather than using one configuration for every size. LEDs offer efficient operation, long life, stable illumination, fast switching and lower maintenance, and the modules and drivers should suit the sign dimensions and project electrical architecture.
How are legend, character height and sign size determined?
The legend is established from the approved signage schedule and may show taxiway and location identifiers, directional arrows, holding-position information, stand numbers, gate identifiers and apron information. Character height, spacing and the overall legend configuration come from the required viewing distance and applicable project criteria. Overall dimensions follow from the legend and character configuration, and larger signs may need additional support or structural provisions.
How are back-lit signs mounted, and must they be frangible?
Arrangements include ground-mounted supports, dedicated sign posts, base-mounted assemblies, adjustable supports and frangible or breakaway supports. Mounting must be stable while maintaining required aircraft and vehicle clearances. Signs on the movement area must be frangible and low enough to clear aircraft propellers and engine pods, and the sign height, distance from the pavement edge and frangible point should be confirmed in the airfield safety and clearance assessment.
What electrical arrangements do airfield signs use?
Airfield signs normally run on a series circuit (constant current, through an isolating transformer) or a parallel circuit (constant voltage). The LED driver must suit the transformer secondary or supply voltage and respond correctly to the regulator brightness steps. Also confirm rated power and current, switching, dimming and control interface, surge protection and earthing, and confirm the electrical interface before procurement.
What is checked at commissioning, and how are signs maintained?
Commissioning covers physical inspection of mounting and supports, electrical connections, illumination testing and legend visibility, luminance and uniformity where required, switching, and a night-time check of orientation, with final installation details recorded. Maintenance covers cleaning the sign face, checking for damage, inspecting mounting hardware, cable entries and electrical connections, checking LED modules and drivers, and looking for moisture ingress, legend condition, colour and luminance changes and corrosion. LED systems reduce routine light-source replacement, but the complete sign assembly should still be inspected periodically.
What are the common problems with back-lit signs?
Uneven illumination points to LED or optical component problems, contamination or internal deterioration. Reduced luminance can come from LED degradation, driver faults, supply problems or a contaminated sign face. Moisture ingress comes from damaged seals, cable-entry problems or enclosure deterioration. A damaged sign face reduces legend clarity and should be assessed promptly, and loose, bent or corroded supports should be inspected and repaired.
Is it safe to work on sign boards while the circuit is energised?
No. An open series circuit driven by a constant-current regulator can produce dangerously high voltage, and opening, cutting or disconnecting any part of an energised circuit can cause serious injury or death. De-energise the circuit at the regulator, apply the site lock-out / tag-out procedure, use the series circuit cut-out switch or an approved isolation device, and work under the airport permit-to-work system. See the electrical safety warning on this page.
Which standards apply to back-lit sign boards?
References include ICAO Annex 14 Vol. I (Chapter 5, signs; Appendix 1, colours; Appendix 4, taxiing guidance sign design), ICAO Doc 9157 Part 4, FAA AC 150/5345-44L and AC 150/5340-18H, DGCA India CAR Section 4, and airport-specific signage specifications and approved signage schedules. Confirm the applicable standard and edition for each project before final technical approval.
What should be provided when requesting or replacing a sign board?
Provide the airport or project name, sign type, approved legend, character height and number of characters, arrow or symbol requirements, required dimensions and installation location, mounting and frangibility requirements, illumination requirements, electrical supply and control requirements, environmental conditions, applicable project standards and required documentation. For replacement or retrofit, check the existing foundations, support arrangements, cable routes and electrical interfaces before selecting the replacement unit.
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
Request Back-Lit Signage Configuration
Need a back-lit sign board for a taxiway, runway-holding position, apron or aircraft stand? Send the sign type, approved legend, character height, required dimensions, installation location and electrical requirements. We can help determine the back-lit configuration, internal illumination arrangement, mounting solution and project documentation.
- Emailprecisionaglsolutions@gmail.com
- Websiterahulsharmaagl.in
- LinkedInPrecision AGL Solutions
- Phone+91 98214 96412
Engineering Note
Sign dimensions, legend configuration, light source, luminance, optical uniformity, internal illumination, mounting, frangibility, electrical interface and environmental protection are project-dependent.
Final selection should be based on the approved airport signage layout, applicable aviation requirements and the current project specification.
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.