Airfield Visual Aids
Landing T / Landing Direction Indicator
A clear visual indication of preferred landing and take-off direction
The Landing T is an aerodrome visual aid that gives pilots a clear indication of the preferred landing and take-off direction. Precision AGL Solutions supplies Landing T configurations for airports, airfields and other aerodromes where a visual landing-direction indicator is required.
Supplied by Precision AGL Solutions
Product Overview
Landing T / Landing Direction Indicator
What It Is
The Landing T (also called a landing tee or Landing Direction Indicator) is a horizontal T-shaped ground signal that can be seen from the air. It shows the direction in use for landing and take-off: aircraft land and take off parallel to the shaft of the T, towards the cross arm (ICAO Annex 2, Appendix 1), unless otherwise authorised by air traffic services.
The aerodrome sets it to the direction in use. It is not the same as a free-swinging wind tee, which is a wind direction indicator that turns with the wind.
Configuration
The final configuration is selected according to the aerodrome layout, operating requirements, visibility conditions, installation location and applicable aviation regulations.
Applications
Where Landing Direction Indicators Are Used
AirportsCivil airports that provide a visual landing-direction signal.
AerodromesLicensed and unlicensed aerodromes with a signal area.
General aviationGeneral aviation and flying-club airfields.
Signal areasInstallation in or beside the aerodrome signal area, where provided.
Training airfieldsFlying-training airfields with circuit traffic.
Remote facilitiesRemote and island airstrips.
Wind-indicator areasPlaced with the wind direction indicator and, where used, the segmented circle system.
UpgradesAirfield upgrade and rehabilitation projects.
The Landing T should be located where it is clearly visible to aircraft operating in the vicinity of the aerodrome.
Operating Principle
A Simple Visual Representation of Landing Direction
How It Works
Its orientation is set to the approved direction in use. It must be re-set whenever the runway in use changes: a Landing T left in the old position gives pilots wrong information. The operating procedure should define who changes it, when, and how the change is checked, and where the indicator is manually repositioned its position must always match the current approved direction.
Used With Other Information
The Landing T is a visual aid and should be considered together with other available operational information, including:
- Wind direction indicator (windsock), which the Landing T does not replace
- Runway condition
- Air traffic procedures
- Applicable aerodrome operating instructions
Main Components
What a Typical Landing T Assembly May Include
- Landing T indicator
- Horizontal cross member
- Directional stem
- Support structure
- Pivot or orientation mechanism, where applicable
- Ground mounting arrangement
- Base or foundation
- Fixing hardware
- Identification or orientation markings
- Optional illumination arrangement where specified
Exact construction depends on the selected configuration.
Technical Data
Specification Summary
| Parameter | Specification |
|---|---|
| Product Type | Landing T / Landing Direction Indicator |
| Application | Landing and take-off direction indication |
| Indicator Configuration | T-shaped directional arrangement |
| Shape and Minimum Dimensions | As given in ICAO Annex 14 Vol. I, Chapter 5 (landing T figure); not smaller than the minimum |
| Material | Project/manufacturer-specific |
| Surface Finish | Weather-resistant finish |
| Colour | White or orange, whichever contrasts best with the background against which it is viewed |
| Orientation | Fixed or adjustable, configuration-specific |
| Mounting | Ground-mounted, horizontal |
| Location | Conspicuous place on the aerodrome, normally in the signal area |
| Rotation/Pivot | Where applicable |
| Foundation | Site-specific |
| Visibility | Clearly visible to aircraft in the circuit and on approach |
| Illumination | Required where used at night: illuminated or outlined by white lights |
| Wind Performance | Site/manufacturer-specific |
| Environmental Protection | Outdoor aerodrome application |
| Weight | Model-specific |
Note: Exact dimensions, material, colour, foundation arrangement, rotation mechanism and illumination requirements should be confirmed against the selected product and applicable project specification.
Construction & Orientation Mechanism
Recognisable, Durable and Securely Positioned
Indicator Construction
The Landing T should provide a distinctive, easily recognisable shape, with sufficient strength for continuous outdoor exposure while maintaining the required visual characteristics. Material selection may consider:
- Mechanical strength
- Weight
- Corrosion resistance
- UV exposure
- Temperature variation
- Wind loading
- Maintenance requirements
Provide suitable protective treatment where the environment requires it.
Orientation Mechanism
Depending on design, the Landing T may incorporate a mechanism that permits its orientation to be changed when the preferred landing direction changes. It should provide:
- Secure positioning
- Controlled movement
- Reliable locking
- Resistance to environmental effects
- Ease of authorised operation
- Clear indication of the selected direction
It should not allow unintended movement under normal conditions. For manual repositioning, the airport's approved operating procedure should define who is authorised to change the orientation and under what conditions.
Visibility & Installation Location
Visible from the Approach, Safe on the Ground
Visibility — Site Selection Considers
- Aircraft viewing direction
- Runway orientation
- Terrain
- Buildings
- Trees and vegetation
- Other structures
- Airfield lighting
- Meteorological equipment
- Adjacent visual aids
The indicator should remain distinguishable from its background under expected operating conditions.
Installation Location Considerations
- Visibility from the relevant approach area
- Relationship to the runway
- Clearance from aircraft movement areas
- Obstacle limitations
- Access for maintenance
- Foundation conditions
- Drainage
- Security
- Compatibility with other airfield equipment
Established as part of the aerodrome visual-aid design; it should not create an unacceptable hazard or obstruction.
Foundation, Mounting & Colour
Securely Mounted and Clearly Identified
Foundation and Mounting
The support structure should be securely mounted to a suitable foundation or approved ground installation arrangement. Foundation requirements depend on:
- Indicator dimensions
- Support height
- Structural arrangement
- Wind loading
- Soil conditions
- Installation environment
- Local structural requirements
For permanent installations, coordinate foundation design with the project's civil and structural requirements.
Colour and Visual Identification
The Landing T is normally white or orange, chosen for the best contrast against the background it is viewed against (for example white on grass, orange on light pavement), with colour and surface characteristics complying with applicable aviation visual-aid requirements.
Where an airport authority specifies a colour, finish, reflective property or pattern, the project specification should govern.
Night Illumination & Electrical
For Night-Time or Low-Light Operation
Illumination Design Considers
- Visibility
- Uniformity
- Light intensity
- Power supply
- Environmental protection
- Maintenance access
- Glare
- Compatibility with surrounding aerodrome lighting
ICAO Annex 14 requires the Landing T, where used at night, to be either illuminated or outlined by white lights. Outline lights must show the complete T shape, so a failed lamp distorts the signal. The final arrangement should follow the applicable project and aerodrome visual-aid requirements.
Electrical Requirements
For non-illuminated installations, no electrical supply is normally required for the indicator itself. Where an illuminated configuration is specified, electrical design may include:
- Supply voltage
- Lighting load
- Cable type
- Protective devices
- Earthing/bonding
- Isolation
- Cable routing
- Weatherproof connections
- Lighting control
Components should be suitable for the installation environment, and lights and fittings should be low enough not to endanger aircraft or vehicles. Where outline lights are fed from an airfield lighting series circuit, the usual series-circuit rules apply: use isolating transformers and never open an energised series circuit.
Installation Procedure
A Typical Installation Sequence
- Confirm the approved installation location
- Verify runway and operating-direction requirements
- Confirm foundation and civil works
- Install the support structure
- Install the Landing T assembly
- Check orientation and movement
- Secure the indicator in the required position
- Install optional illumination equipment where applicable
- Complete electrical connections if required
- Verify visibility from the intended aircraft operating area
- Complete inspection and commissioning documentation
The actual procedure should follow the manufacturer's installation instructions and approved project drawings.
Commissioning, Inspection & Maintenance
From Acceptance into Service to Routine Care
Commissioning Checks
- Structural stability
- Foundation condition
- Mechanical fasteners
- Correct indicator geometry
- Correct orientation
- Operation of the orientation mechanism
- Locking arrangement
- Visibility from the relevant operating area
- Illumination, where fitted
- Electrical connections, where applicable
- Clearance from surrounding equipment
- Identification and documentation
Accept into service only after the required inspections are complete.
Routine Inspection
- Indicator condition
- Structural damage
- Corrosion
- Surface deterioration
- Colour fading
- Loose fasteners
- Foundation condition
- Pivot or orientation mechanism
- Locking mechanism
- Visibility
- Orientation matches the direction in use
- Illumination or outline lights, all lamps working and T shape complete
Set maintenance intervals from the airport maintenance programme and environmental conditions.
Troubleshooting
Symptoms, Causes and Checks
Landing T Difficult to Reposition
Possible causes
- Corrosion
- Contamination
- Mechanical damage
- Seized pivot
- Damaged bearings
- Locking mechanism failure
Inspect and service the mechanism rather than forcing it.
Indicator Moves Unintentionally
Possible causes
- Loose locking mechanism
- Mechanical wear
- Damaged support
- Excessive movement in the pivot assembly
Secure the indicator in accordance with the approved operating arrangement.
Poor Visibility
Possible causes
- Faded surface
- Damaged indicator
- Incorrect installation position
- Background obstruction
- Vegetation growth
- Insufficient illumination where fitted
Review the complete visual-aid arrangement.
Illumination Not Operating
Possible causes
- Loss of electrical supply
- Failed light source
- Cable fault
- Loose connection
- Protective device operation
- Damaged lighting equipment
For illuminated configurations, follow the approved electrical maintenance procedure.
Indicator Shows the Wrong Direction
Possible causes
- Not re-set after a change of runway in use
- Locking mechanism slipped
- Wrong reference alignment at installation
Treat as a safety issue: correct it at once under the aerodrome operating procedure.
Outline Lights Partly Out
Possible causes
- Failed lamps or LED modules
- Open or faulty circuit section
- Transformer or connector fault
A broken outline distorts the T shape at night. Repair promptly and follow the airport lighting maintenance procedure.
Replacement
Replacing an Existing Landing T
Verify Before Replacing
- Existing dimensions
- Indicator configuration
- Material
- Colour
- Support arrangement
- Foundation interface
- Orientation mechanism
- Illumination requirement
- Installation location
- Applicable airport specification
Compatibility
For replacement projects, photographs and existing dimensional information can help confirm compatibility.
Procurement Checklist
Before Requesting a Landing T
Please provide:
- Aerodrome type
- Runway configuration
- Required indicator dimensions
- Installation location
- Fixed or adjustable orientation
- Material preference or specification
- Colour requirement
- Illumination requirement
- Foundation information
- Environmental conditions
- Airport authority specification
- Existing indicator information for replacement projects
A site layout or photograph of the existing installation is useful for retrofit applications.
Documentation & Standards
Technical Documentation and References
Documentation
- Product datasheet
- Dimensional drawing
- Material specification
- Foundation requirements
- Mounting details
- Orientation mechanism details
- Illumination details, where applicable
- Installation instructions
- Maintenance instructions
- Inspection checklist
- Project-specific compliance documentation
Standards / References
Design, install and maintain according to the applicable aerodrome visual-aid requirements and project specifications. Potential references include:
- ICAO Annex 14 Vol. I, Chapter 5, para 5.1.2 (landing direction indicator: location, shape and minimum dimensions, colour, night lighting)
- ICAO Annex 2, Appendix 1 (meaning of the landing T as a ground signal)
- FAA AC 150/5340-5D (Segmented Circle Airport Marker System), where applicable
- DGCA India CAR Section 4 and AIP India aerodrome requirements
- Applicable national civil aviation regulations
- Airport authority standards
- Project-specific visual-aid specifications
- Applicable structural requirements
- Manufacturer installation instructions
Confirm the applicable standard edition and local regulatory requirements before procurement.
Why Choose Precision AGL Solutions
Selection Based on the Aerodrome Environment
We support airport visual-aid selection based on the actual aerodrome operating environment. For Landing T applications, selection can consider:
- Runway configuration
- Preferred landing-direction arrangement
- Visibility requirements
- Indicator dimensions
- Mounting location
- Foundation requirements
- Environmental conditions
- Fixed or adjustable orientation
- Optional illumination
- Airport authority specifications
This supports selection of a complete visual-aid arrangement suitable for new installations and replacement projects.
FAQ
Landing T / Landing Direction Indicator — Frequently Asked Questions
What is a Landing T and how is it read?
A Landing T, also called a landing tee or Landing Direction Indicator, is a horizontal T-shaped ground signal visible from the air. It shows the direction in use: aircraft land and take off parallel to the shaft of the T, towards the cross arm (ICAO Annex 2, Appendix 1), unless otherwise authorised by air traffic services.
Is a Landing T the same as a wind tee or windsock?
No. A free-swinging wind tee is a wind direction indicator that turns with the wind, whereas the Landing T is set by the aerodrome to the direction in use. It does not replace the windsock and should be considered together with the wind direction indicator, runway condition, air traffic procedures and aerodrome operating instructions.
Who changes the Landing T, and when?
It must be re-set whenever the runway in use changes, because a Landing T left in the old position gives pilots wrong information. The operating procedure should define who changes it, when and how the change is checked, and where it is manually repositioned its position must always match the current approved direction.
What colour should a Landing T be?
It is normally white or orange, whichever contrasts best with the background against which it is viewed, for example white on grass and orange on light pavement. Where an airport authority specifies a colour, finish or pattern, the project specification governs.
Does a Landing T need to be lit at night?
ICAO Annex 14 requires the Landing T, where used at night, to be either illuminated or outlined by white lights. Outline lights must show the complete T shape, so a failed lamp distorts the signal and should be repaired promptly.
Where should a Landing T be installed?
At a conspicuous place on the aerodrome, normally in the signal area, where it is clearly visible to aircraft in the circuit and on approach. It is often placed with the wind direction indicator and, where used, the segmented circle system. Site selection considers viewing direction, runway orientation, terrain, buildings, trees, clearance from movement areas and obstacle limitations.
Should the Landing T be fixed or adjustable?
Orientation is configuration-specific. An adjustable design uses an orientation mechanism that should provide secure positioning, controlled movement, reliable locking, resistance to environmental effects, ease of authorised operation and a clear indication of the selected direction, and it should not allow unintended movement.
Which standards cover the Landing T?
Shape and minimum dimensions are given in ICAO Annex 14 Volume I, Chapter 5, paragraph 5.1.2, which also covers location, colour and night lighting, and the indicator should not be smaller than the minimum. The meaning of the signal is in ICAO Annex 2, Appendix 1. Other references may include FAA AC 150/5340-5D (segmented circle), DGCA India CAR Section 4 and AIP India.
How is a Landing T installed and inspected?
Confirm the approved location and operating-direction requirements, prepare the foundation, install the support structure and assembly, check orientation and movement, secure the indicator, and verify visibility from the intended aircraft operating area. Routine inspection covers structural damage, corrosion, colour fading, fasteners, foundation, the pivot and locking mechanism, visibility and that the orientation matches the direction in use.
What if the Landing T shows the wrong direction?
Treat it as a safety issue and correct it at once under the aerodrome operating procedure. Possible causes are that it was not re-set after a change of runway in use, the locking mechanism slipped, or the reference alignment was wrong at installation.
Does an illuminated Landing T need an electrical supply?
Non-illuminated installations normally need no electrical supply for the indicator itself. Illuminated configurations need electrical design covering supply voltage, lighting load, cable, protection, earthing, isolation and weatherproof connections, and fittings should be low enough not to endanger aircraft or vehicles. Where outline lights are fed from an airfield lighting series circuit, use isolating transformers and never open an energised series circuit.
What should I provide when requesting a Landing T?
Provide the aerodrome type, runway configuration, required indicator dimensions, installation location, fixed or adjustable orientation, material and colour requirements, illumination requirement, foundation information, environmental conditions and the airport authority specification. For replacement, send existing indicator information, a site layout or photographs.
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 Airport Visual-Aid Selection
Need a Landing T for a new airfield, runway upgrade or replacement project? Send us the runway configuration, required indicator dimensions, installation location, orientation arrangement, illumination requirement and applicable airport specification, and we can review the application and support selection of a suitable Landing Direction Indicator.
- Emailprecisionaglsolutions@gmail.com
- Websiterahulsharmaagl.in
- LinkedInPrecision AGL Solutions
- Phone+91 98214 96412
Engineering Note
The Landing T is an aerodrome visual aid and should be integrated with the overall operational and visual-aid arrangement of the airport. Its orientation, visibility, location, structural arrangement and any associated illumination should be established according to the applicable aerodrome requirements and approved airport operating procedures.
Where the indicator is adjustable, the method and authority for changing its orientation should be clearly defined as part of the aerodrome operating procedure. The main operational risk is a Landing T that does not match the runway in use, so its position should be checked at every runway change and at each routine inspection.
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.