Airfield Signs
Airfield Direction Sign for Taxiway Routing
Clear routing information at intersections and movement areas
Direction signs show pilots and vehicle operators which way to go: taxiway routes, runway connections and apron destinations, with legend, arrows, colour and mounting taken from the approved signage plan.
Supplied by Precision AGL Solutions
Product Overview
Airfield Direction Sign
What It Is
Direction signs give clear visual routing information to pilots and vehicle operators at taxiway intersections and other movement locations, identifying available taxiway routes, runway connections, apron routes and approved destinations.
They are distinct from location signs (current position) and mandatory instruction signs (restrictions or holding requirements). Configuration follows the approved signage plan, taxiway geometry, viewing direction, standard and project electrical requirements.
Configurations
- Single- or multi-direction
- Left-turn, right-turn, straight-ahead or combined arrows
- Internally illuminated (LED or other approved source) or retroreflective where permitted
- Series-circuit (constant-current) or parallel (constant-voltage) powered
- Single- or multi-face where required
Final configuration is based on the approved movement-area signage layout.
Applications
Where Direction Signs Are Used
Taxiway intersectionsIndicate the available routes from the intersection.
Runway connectionsRoute toward taxiways, aprons or other areas.
Apron routingTerminal, stand, remote-stand, maintenance and cargo routes.
Complex networksHelp pilots select the intended route.
At runway interfaces, coordinate with runway holding position, mandatory instruction sign, runway designation, taxiway centreline and lighting.
Direction vs Other Signs
Direction Sign vs Location Sign
| Sign Type | Function | Typical Information |
|---|---|---|
| Direction Sign | Indicates route or destination | Taxiway / destination + arrow |
| Location Sign | Identifies current position | Taxiway / location designation |
| Mandatory Instruction Sign | Communicates a restriction | Runway holding, NO ENTRY, etc. |
| Other Information Signs | Further guidance information | Destination, runway exit / vacated and intersection take-off signs |
Configure a direction sign for the intended route, not the aircraft's current location. Under ICAO Annex 14, direction, location and destination signs are all classed as information signs; mandatory instruction signs are a separate category.
Arrows & Legend
Directional Arrows and Legend Configuration
Directional Arrows
- Left-turn and right-turn arrows
- Straight-ahead indication
- Multiple or combined arrows
Arrow orientation must correspond exactly to the physical route. An incorrect arrow gives misleading operational information; verify every arrow against the approved taxiway layout before manufacture.
Arrow angle should represent the real turn geometry. Where several arrows share one sign, group them by turn direction and, where a location sign is combined with them, separate the panels with black vertical delineators. Confirm panel order against ICAO Annex 14 Chapter 5 and FAA AC 150/5340-18H.
Legend
Normally identifies the taxiway, runway or destination for the route:
- Taxiway and runway designations
- Apron, terminal-area and stand destinations
- Other approved destinations
Take the exact legend from the approved signage schedule.
Multiple-Direction Signs
Several Routes, One Assembly
Possible Designs
- Two- and three-direction configurations
- Multiple taxiway destinations
- Separate arrows for each route
Requirement
The arrangement must remain visually clear and conform to the applicable sign-design standard.
Sign Colour
Black on Yellow
ICAO and FAA Signage
Direction signs use a black inscription on a yellow background under both ICAO Annex 14 and FAA rules (FAA type L-858Y), distinguishing routing information from other signs. Destination and other information signs use the same colours.
Contrast With
- Location signs: yellow on black
- Mandatory instruction signs: white on red
Colour must meet the chromaticity and luminance limits of the applicable standard; confirm colour, border and optical characteristics against it.
ICAO & FAA Applications
Standard-Specific Approach
ICAO
Direction signs are part of the movement-area visual guidance system, giving route information at taxiway intersections. Coordinate with:
- Taxiway designations, location and mandatory instruction signs
- Pavement markings, taxiway lighting
- Runway-holding positions
The approved aerodrome signage layout determines legend, arrows and position.
FAA (L-858)
Direction signs are part of the FAA runway and taxiway sign system. The current L-858 specification determines:
- Classification, size, style
- Legend, arrow configuration, character height
- Colour, illumination, electrical interface
- Mounting and environmental performance
Select as part of the complete airport signage system, not as an isolated product.
Character Height & Dimensions
Readability From the Cockpit
Character Height Depends On
- Applicable standard and sign type
- Viewing distance, taxiway geometry
- Cockpit viewing conditions
- Operating environment, approved schedule
Do not select it solely from available sign dimensions.
Overall Dimensions Depend On
- Character height and count
- Number of directional panels, arrow configuration
- Legend arrangement, border requirements
- Sign type, illumination arrangement
FAA: L-858 standardized configurations. ICAO: Annex 14 and aerodrome design guidance.
Illumination & LED
Contrast and Uniformity
Options
- Internally illuminated
- LED illuminated
- Series-circuit (constant-current) or parallel (constant-voltage) powered
- Retroreflective where permitted
- Other approved project-specific configurations
Provide sufficient contrast and uniformity for night and reduced-light operations. Annex 14 requires illuminated signs in runway visual range below 800 m, at night with instrument runways, and at night with non-instrument runways of code number 3 or 4; otherwise a retroreflective sign may be acceptable. Confirm the requirement with the airport authority. Sign luminance should follow the airfield brightness steps.
LED Direction Sign
- Long life, reduced lamp replacement
- Lower maintenance, efficient operation
- Stable, consistent optical output
- Compatible with modern airfield lighting
LED construction must still meet the complete sign's optical, electrical and environmental requirements.
Electrical Configuration
Series Circuit, Parallel Supply or LED Driver
Series Circuit
Connected to the constant-current circuit through an isolating transformer; brightness follows the CCR steps.
Parallel (Constant-Voltage)
Supplied from a constant-voltage circuit where the airport uses parallel sign circuits.
LED Driver
Dedicated driver or power-conversion arrangement.
CCR Compatibility
- Circuit current, transformer rating
- Sign load and number of signs
- Circuit configuration
- Brightness steps and sign luminance at each step
- Monitoring
Principle
Match the sign to the complete airfield lighting circuit and confirm the configuration during technical selection. Never open an energised series circuit: isolate and lock off the CCR first.
Mounting & Frangibility
Support Arrangement
Typical Components
- Frangible support posts, support channels
- Mounting brackets, base plates, anchor hardware
- Frangible couplings, cable-entry provisions
Signs on the movement area must be frangible and low enough to clear propellers and engine pods, while keeping the required position, visibility and edge clearance.
Frangibility
- Frangible posts, breakaway couplings
- Lightweight support assemblies
- Controlled failure interfaces
Evaluate frangibility for the complete sign/support assembly.
Environmental Performance
Outdoor Airport Environment
Exposure
- Rain, humidity, dust, sand
- UV exposure, temperature cycling, wind
- Cleaning agents, de-icing chemicals
- Coastal or salt-laden environments
Construction May Include
- Corrosion-resistant materials
- Weather-resistant housing
- UV-resistant optical materials
- Sealed electrical compartments, drainage
- Protected fasteners, durable coatings
Technical Data
Typical / Required Information
| Parameter | Typical / Required Information |
|---|---|
| Product type | Airfield direction sign |
| Application | Taxiway and movement-area routing |
| Sign category and colour | Direction (information) sign: black legend on yellow background |
| FAA classification | L-858Y (yellow background, black legend); size, class and style per AC 150/5345-44L |
| Legend and arrow configuration | Project-specific |
| Character height, dimensions | Standard / project specific |
| Background and legend colour | Black legend on yellow background |
| Illumination | Internally illuminated; retroreflective only where the regulation and signage plan permit |
| Light source | LED or approved technology |
| Luminance and uniformity | Per applicable standard, at each brightness step |
| Electrical input | Project / equipment specific |
| Circuit type | Series (constant-current) via isolating transformer, or parallel (constant-voltage) |
| Housing | Airfield-grade construction |
| Mounting and frangibility | Elevated / ground-mounted; per applicable requirement |
| Environmental performance | Airfield outdoor environment |
| Operating temperature, cable entry, weight | Equipment / manufacturer specific |
| Documentation | Datasheet, drawing, compliance documentation |
Confirm exact values against the selected configuration and current product documentation.
Direction Sign Selection Process
Eight Steps to Specify a Sign
Identify intersectionExact taxiway / movement-area intersection
Identify routesAll destinations to indicate
Confirm functionDirection, not location / mandatory / information
Confirm legendApproved signage schedule
Confirm arrowsCheck against physical geometry
Confirm standardICAO, FAA, national, airport spec
Confirm illuminationIlluminated, LED, series or parallel circuit
Confirm mountingSupport, height, foundation, frangibility, orientation
Installation Considerations
Position, Orientation and Visibility
Position
Locate at the approved position relative to the intersection, giving pilots sufficient time to identify and interpret the routing information.
Orientation
Face the intended aircraft approach direction. Traffic approaching from multiple directions may need multiple faces or assemblies.
Visibility
- Daylight, night, low ambient light
- Reduced visibility, rain, contamination
Consider potential visual obstructions during site installation.
Coordination With Pavement Markings
The Sign Must Represent the Approved Route
- Taxiway centreline and edge markings
- Runway-holding position markings
- Taxiway designation
- Location signs, mandatory instruction signs
- Taxiway centreline and edge lights
Commissioning
Typical Procedure
- Verify sign type
- Verify the legend
- Verify all arrows
- Confirm sign location
- Confirm orientation
- Check support and foundation
- Verify frangible components where applicable
- Inspect housing
- Energize the sign
- Check illumination at every brightness step
- Check colour
- Check optical uniformity
- Verify electrical operation
- Confirm visibility from the intended taxi route
- Record the installed configuration
Final acceptance follows the airport's approved inspection procedure.
Maintenance
Routine Inspection
Sign Face
- Scratches, cracks
- Contamination, discolouration, fading
- Physical damage
Illumination
- LED failures, dark areas
- Uneven brightness, reduced output
- Driver faults
Housing
- Corrosion, water ingress
- Seal deterioration, loose components
- Structural damage
Mounting
- Posts, fasteners, base plates
- Frangible couplings
- Foundation, alignment
Common Problems
Causes and Recommended Actions
| Problem | Possible Causes | Recommended Action |
|---|---|---|
| Wrong arrow direction | Manufacturing error, incorrect installation, changed geometry, outdated drawing | Verify every arrow against the current approved layout before installation |
| Incorrect taxiway designation | Renaming, airport expansion, outdated schedule, manufacturing error | Confirm legend against the latest approved signage plan |
| Poor night visibility | LED failure, reduced luminance, dirty face, optical deterioration, supply problem | Inspect sign, electrical interface and optical system |
| Sign obstructed | New structures, vegetation, lighting equipment, parked aircraft/vehicles, apron changes | Review the complete line of sight from the intended taxi route |
Procurement Checklist
For a Quotation, Provide
- Airport / project
- Governing standard
- Installation location
- Taxiway intersection
- Exact legend
- Arrow directions
- Character height
- Quantity
- Sign dimensions if specified
- Illuminated / retroreflective
- LED requirement
- Electrical supply
- Series-circuit requirements
- Mounting arrangement
- Frangible requirements
- Environmental requirements
- Required documentation
An approved airport signage plan or sign-face drawing is strongly recommended for multi-direction signs.
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 & References
Verify the Applicable Edition
Relevant References
- ICAO Annex 14 Vol. I — Aerodromes (Chapter 5 signs; Appendices 1 and 4)
- ICAO Doc 9157 Part 4 — Aerodrome Design Manual, Visual Aids
- FAA AC 150/5345-44L — Specification for Runway and Taxiway Signs
- FAA AC 150/5340-18H — Standards for Airport Sign Systems
- DGCA India CAR Section 4 — Aerodrome Standards
- Airport-specific specifications and approved signage plans
- Manufacturer installation and maintenance documents
Note
Verify the applicable current edition and any amendments before procurement.
Documentation & Support
What Precision AGL Solutions Provides
Documentation
- Product datasheet, sign-face and GA drawings
- Legend layout, arrow configuration drawing
- Electrical schematic, mounting drawing
- Foundation and frangibility documentation
- Photometric information, material specification
- Installation and maintenance manuals
- Compliance documentation where applicable
Support
- New construction, taxiway development, runway rehabilitation
- Apron expansion, terminal-area development
- Movement-area modernization, replacement, LED upgrades
- ICAO-based installations and FAA L-858 applications
Includes sign type selection, legend review, arrow configuration, dimensional review, electrical-interface coordination, mounting selection and documentation.
FAQ
Airfield Direction Sign — Frequently Asked Questions
What is an airfield direction sign?
A direction sign gives clear visual routing information to pilots and vehicle operators at taxiway intersections and other movement locations. It identifies the available taxiway routes, runway connections, apron routes and approved destinations. Its configuration follows the approved signage plan, taxiway geometry, viewing direction, the applicable standard and the project electrical requirements.
How does a direction sign differ from a location sign and a mandatory instruction sign?
A direction sign indicates a route or destination, normally a taxiway or destination designation with an arrow. A location sign identifies the current position, and a mandatory instruction sign communicates a restriction such as a runway holding position or NO ENTRY. A direction sign is configured for the intended route, not for the aircraft’s current location. Under ICAO Annex 14, direction, location and destination signs are all information signs, while mandatory instruction signs are a separate category.
What colour is a direction sign?
Direction signs use a black inscription on a yellow background under both ICAO Annex 14 and FAA rules, where the FAA type is L-858Y. Location signs are yellow on black and mandatory instruction signs are white on red. The colour must meet the chromaticity and luminance limits of the applicable standard, so confirm colour, border and optical characteristics against it.
Which standards apply to direction signs?
References include ICAO Annex 14 Vol. I (Chapter 5 on signs, with Appendices 1 and 4), ICAO Doc 9157 Part 4, FAA AC 150/5345-44L for runway and taxiway signs, FAA AC 150/5340-18H for sign systems, DGCA India CAR Section 4, and the airport’s own specifications and approved signage plans. For FAA installations the current L-858 specification determines classification, size, style, legend, arrow configuration, character height, colour, illumination, electrical interface, mounting and environmental performance. Verify the applicable edition and any amendments before procurement.
How are arrows and multi-direction signs arranged?
Arrow orientation must correspond exactly to the physical route, and every arrow should be checked against the approved taxiway layout before manufacture. The arrow angle should represent the real turn geometry. Where several arrows share one sign, group them by turn direction and, where a location sign is combined with them, separate the panels with black vertical delineators. Confirm the panel order against ICAO Annex 14 Chapter 5 and FAA AC 150/5340-18H. Two- and three-direction signs are possible as long as the arrangement stays visually clear and conforms to the sign-design standard.
Does a direction sign have to be illuminated?
Annex 14 requires illuminated signs where runway visual range is below 800 m, at night with instrument runways, and at night with non-instrument runways of code number 3 or 4. Otherwise a retroreflective sign may be acceptable, so confirm the requirement with the airport authority. Sign luminance should follow the airfield brightness steps. An LED construction gives long life and lower maintenance, but it must still meet the complete sign’s optical, electrical and environmental requirements.
How is a direction sign powered?
A direction sign is either connected to a series (constant-current) circuit through an isolating transformer, with brightness following the CCR steps, or supplied from a constant-voltage circuit where the airport uses parallel sign circuits. A dedicated LED driver or power-conversion arrangement may also be used. Match the sign to the complete circuit by checking circuit current, transformer rating, the sign load and number of signs, the brightness steps and sign luminance at each step, and any monitoring.
How are character height and sign size decided?
Character height depends on the applicable standard and sign type, the viewing distance, taxiway geometry, cockpit viewing conditions, the operating environment and the approved signage schedule. It should not be selected solely from available sign dimensions. Overall dimensions in turn depend on character height and count, the number of directional panels, the arrow configuration, the legend arrangement, border requirements, sign type and illumination arrangement.
How is a direction sign mounted, and why does it need to be frangible?
Typical components are frangible support posts, support channels, mounting brackets, base plates, anchor hardware, frangible couplings and cable-entry provisions. Signs on the movement area must be frangible and low enough to clear propellers and engine pods, while keeping the required position, visibility and edge clearance. Frangibility should be evaluated for the complete sign and support assembly. The sign should face the intended aircraft approach direction, and traffic approaching from several directions may need multiple faces or assemblies.
What are the common problems with direction signs?
The main problems are a wrong arrow direction (manufacturing error, incorrect installation, changed geometry or an outdated drawing), an incorrect taxiway designation (renaming, airport expansion or an outdated schedule), poor night visibility (LED failure, reduced luminance, a dirty face, optical deterioration or a supply problem) and an obstructed sign (new structures, vegetation, lighting equipment, parked aircraft or vehicles). Verify every arrow against the current approved layout before installation and confirm the legend against the latest approved signage plan.
What should be provided when requesting a quotation for a direction sign?
Provide the airport or project, governing standard, installation location, taxiway intersection, exact legend, arrow directions, character height, quantity and sign dimensions if specified. Also state whether the sign is illuminated or retroreflective, any LED requirement, the electrical supply and series-circuit requirements, the mounting arrangement, frangible requirements, environmental requirements and the documentation needed. An approved airport signage plan or sign-face drawing is strongly recommended for multi-direction signs.
Is it safe to work on a direction sign 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’s permit-to-work system. See the electrical safety warning on this page.
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 Sign Layout & Technical Selection
For an airfield direction sign quotation or technical review, provide the airport/project standard, installation location, taxiway intersection, required destinations, exact legend, arrow directions, character height, illumination requirement and quantity where available. We can support the development or review of direction-sign configurations for taxiways, intersections, apron routes and complex movement areas.
- Emailprecisionaglsolutions@gmail.com
- Websiterahulsharmaagl.in
- LinkedInPrecision AGL Solutions
- Phone+91 98214 96412
Engineering Note
Direction signs are safety-critical components of the airport visual guidance system. Legend, arrow direction, colour, character dimensions, illumination, mounting location and support arrangement should be established from the applicable aviation standard and approved airport signage plan.
Always check the sign against the current taxiway geometry and approved movement-area routing before manufacture or installation. Exact dimensions, luminance, electrical characteristics and mounting details are standard- and project-specific: confirm the current standard and manufacturer documentation before procurement or installation.
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.