Runway Distance Marker Boards

What It Is

Runway distance markers give clear visual information about runway distance and help pilots maintain operational awareness. Positioned alongside the runway or at designated locations, the marker boards present distance information in a simple, highly visible format.

Supplied as non-illuminated, retroreflective or illuminated boards, selected according to runway layout, operational requirements, ambient lighting and aerodrome standard.

Five Design Elements

• Legend — distance or identification information
• Marker face — surface carrying the legend
• Visibility treatment — painted, retroreflective or illuminated
• Support structure — posts, brackets, foundations
• Installation interface — physical and any electrical connection

Treat the assembly as an integrated airfield product, not a printed board.

FAA Practice

Under FAA practice (AC 150/5340-18H and AC 150/5345-44L) a runway distance-remaining sign has a black face with a white numeral. The numeral gives the remaining runway length in thousands of feet. The sign is normally internally illuminated and installed beside the runway. Legend colour is therefore set by the standard and is not a free project choice. On FAA-governed projects the distance-remaining sign is the illuminated type under AC 150/5345-44L, so confirm with the authority before offering painted or retroreflective-only boards for such a project.

ICAO and Other Authorities

Annex 14 deals with runway distance information differently from the FAA, so on ICAO-governed projects confirm with the national authority or airport specification whether a distance-remaining sign is required, its legend format (metres or feet), colours, size and spacing, before drawings are approved.

The Marker May Communicate

• Remaining runway distance
• Distance-related runway information
• Operational identification
• Supplemental runway information

Particularly important where multiple markers form a coordinated sequence: review the whole sequence for correct identification and position.

Legend Design Considerations

• Numerals or text, character height, stroke width
• Spacing and alignment
• Border or edging
• Number of information lines
• Viewing direction, contrast with background

Character Height Factors

• Pilot viewing distance, runway geometry
• Marker position, aircraft operating environment
• Ambient lighting, required recognition time
• Marker dimensions, regulatory requirements

Larger is not automatically better.

Dimensional Considerations

• Board width and height, character height
• Border dimensions, number of characters
• Mounting clearance, support spacing
• Foundation requirements

For replacements, review existing marker dimensions to simplify installation.

Construction Considerations

• Aluminium or other corrosion-resistant material
• Weather-resistant face, UV-resistant finish
• Durable legend surface
• Corrosion-resistant fasteners, reinforced mounting points
• Sealed illuminated enclosure where applicable

Environment

Select materials for site conditions. Coastal, humid, industrial or high-temperature locations may need additional material and protective-finish considerations.

Visibility Is Influenced By

• Marker size, character height, colour contrast
• Retroreflective performance, illumination
• Viewing angle, background, ambient lighting
• Weather and surface cleanliness

Principle

Evaluate the complete installation rather than relying on the nominal appearance of the marker face.

Retroreflective Configuration

Non-powered; enhanced visibility under aircraft lighting.

• Improved night-time recognition
• No dedicated electrical supply
• Reduced electrical maintenance
• Simple installation, reduced infrastructure

Performance can decline from contamination, weathering, UV, damage or ageing: include inspection and cleaning in maintenance.

Illuminated Configuration

Where active illumination is required: internal LED, edge or face illumination, or project-specific assemblies, with adequate visibility, contrast and no excessive glare.

• Required luminance, viewing direction
• Sign-face construction, power availability
• Control requirements, maintenance access
• Airport electrical architecture

LED Benefits

• Long operating life, reduced lamp replacement
• Efficient power consumption, rapid switching
• Consistent illumination, lower maintenance

Select LED modules and power supplies as a coordinated system for uniform illumination.

Electrical Interface Considerations

• Supply voltage, AC or DC operation
• Series-circuit (constant-current, via isolating transformer) or parallel-circuit supply for illuminated boards, with brightness-step control
• Dedicated circuits, airfield lighting control, switching
• Surge protection, earthing and bonding
• Cable entry, maintenance isolation

Review before procurement when installing in an existing airfield lighting network.

Mounting Arrangements

• Single- or two-post mounting
• Ground-supported structures, bracket-mounted assemblies
• Project-specific support frames
• Frangible mounting: equipment in the operational area must be frangible and mounted as low as its function allows (Annex 14, Vol. I, Chapter 9)

Consider marker height, wind loading, foundation type, pavement and aircraft clearance, maintenance access, cable routing.

Frangibility & Airfield Safety

Where the marker is in an aircraft operating environment, evaluate against applicable frangibility and obstacle-clearance requirements across:

• Marker board, support posts, base assembly
• Fasteners, breakaway interfaces
• Foundation, cable routing

Requirements depend on marker location and aerodrome design criteria.

Installation Should Account For

• Runway edge location, shoulder width
• Safety areas, aircraft clearance
• Sightlines, maintenance access
• Drainage, ground conditions

Coordinate With

• Runway edge, threshold, end and centreline lights
• Runway markings
• Mandatory instruction and location signs
• Other marker boards

Provide useful information without visual confusion or obstructing other visual aids.

Activities

• Cleaning the face, removing contamination
• Inspecting retroreflective material, fading, corrosion
• Checking fasteners, support posts, foundations
• Inspecting cable entries
• Checking LED modules and power supplies, verifying illumination

Action

Assess and repair or replace markers that are damaged, faded, heavily contaminated or poorly illuminated.

Existing Installations Can Be Reviewed For

• Board dimensions, support arrangement, foundation
• Legend and visibility condition
• Retroreflective performance
• Electrical configuration
• Compatibility with the replacement

Approach

Where practical, replacement dimensions are coordinated with existing infrastructure to minimize installation work.

Potential References

• ICAO Annex 14, Vol. I – visual aids (Chapter 5) and siting of equipment (Chapter 9); ICAO Doc 9157 Part 4
• FAA AC 150/5340-18H (Standards for Airport Sign Systems), AC 150/5345-44L (Specification for Runway and Taxiway Signs) and AC 150/5340-30J
• National civil aviation regulations
• Airport-specific engineering standards
• Project tender specifications and approved layout drawings

Verify Before Manufacture

Legend, dimensions, colour, character height, location, visibility requirements, mounting and frangibility should be verified against the current applicable standard.

Documentation

• Product datasheets, marker-board and GA drawings
• Legend layouts, mounting details, foundation information
• Electrical information for illuminated versions
• Installation guidance, O&M documentation
• Technical submittals

Why Precision AGL Solutions

• Marker selection, legend and layout coordination
• Retroreflective and illuminated LED options
• Mounting recommendations, electrical interface review
• Replacement and retrofit support, documentation
• Coordination with other signage and lighting equipment

Helps ensure markers function as part of the wider airport visual guidance system.