Mounting Stem
Provides the primary mechanical support interface between the fixture and its mounting assembly.
View Details Mounting Hardware
AGL Extension Stem for Elevated Airfield Lights
Additional mounting height for compatible fixtures
Extension stems for additional mounting height or dimensional adjustment of compatible elevated airfield lighting fixtures.
Manufactured by Precision AGL Solutions
Product Overview
AGL Extension Stem
What It Is
Extension stems provide additional mounting height or dimensional adjustment for compatible airfield lighting fixtures.
They allow the installed elevation of an elevated fixture to be adjusted while maintaining a suitable mechanical interface between the fixture, mounting stem, base and associated mounting hardware.
Mounting Assembly
The extension stem is considered together with the mounting stem, base, fixture and any intermediate coupling so that the complete assembly is compatible.
Applications
Where AGL Extension Stems Are Used
Increasing mounting heightAdditional height for compatible fixtures.
Adjusting installed elevationElevation adjustment of elevated airfield lights.
Clearance from the baseDimensional clearance between a fixture and its base.
RefurbishmentAdapting existing mounting arrangements during refurbishment.
Replacement projectsSupporting selected airfield lighting replacement projects.
Stem & coupling integrationIntegration with compatible mounting stems and frangible couplings.
For compatible elevated airfield lighting installations.
Key Features
What the Extension Stem Provides
Features
- Provides additional mounting height for compatible fixtures
- Available in project-specific lengths
- Configurable diameter and mounting interfaces
- Designed for integration with compatible mounting stems and bases
- Supports selected elevated airfield lighting applications
- Material and finish selected according to installation requirements
- Suitable for new installations and selected retrofit applications
- Allows mounting geometry to be adapted without replacing the complete support assembly
Technical Data
AGL Extension Stem Specification
| Parameter | Specification |
|---|---|
| Length | Selected according to required additional height |
| Diameter | Mounting arrangement dependent |
| Material | Project and application dependent |
| Thread / Interface | Selected to suit compatible components |
| Structural Characteristics | Determined by length, material, geometry and application |
| Fixture Compatibility | Compatible fixture and mounting arrangement dependent |
| Base Compatibility | Selected according to the associated mounting assembly |
| Finish / Coating | Selected according to environmental requirements |
| Installation | Project and equipment dependent |
Mounting Height Adjustment
Additional Elevation Where the Standard Arrangement Falls Short
Selecting Extension Length
The primary purpose of an extension stem is to provide additional elevation where the standard mounting arrangement does not provide the required fixture height.
Select the extension length based on the finished installation level, fixture requirements and complete mounting configuration. Avoid excessive or unnecessary extension where it could affect the mechanical characteristics of the assembly.
Interface & Compatibility
Correct Mechanical Interfaces at Both Ends
Confirm Before Procurement
Extension stems are installed between compatible mounting components and must provide the correct mechanical interfaces at both ends. Confirm thread type, diameter, connection geometry and overall length before procurement.
Consider the stem together with the mounting stem, base, fixture and any intermediate coupling to ensure complete assembly compatibility.
A longer stem also needs enough secondary cable. Route the cable and connector inside the stem so they are not strained, pinched or bent below the cable bend radius.
Stem & Coupling Integration
Mounting Stem and Frangible Coupling Interface
Mounting Stem Integration
An extension stem can be used with a compatible mounting stem where additional height or dimensional adjustment is required. Assess the combined assembly for overall length, alignment and structural suitability.
Where multiple mounting components are combined, the final configuration should remain within the applicable project and equipment requirements.
Frangible Coupling Interface
Where an elevated fixture requires a frangible mounting arrangement, the extension stem may be coordinated with a compatible frangible coupling. Check the complete fixture, coupling, extension and support assembly for interface compatibility.
Do not modify the extension stem in a manner that could alter the intended mechanical or frangible characteristics of the complete mounting arrangement.
Structural Characteristics
Select by Configuration, Not by Length Alone
Structural Suitability
Structural suitability depends on the stem’s material, diameter, length, geometry, connected equipment and installation configuration.
Longer extensions may introduce different mechanical requirements compared with shorter mounting arrangements. Select the final stem configuration according to the fixture and support conditions rather than by length alone.
Adding length raises the fixture and increases the bending load on the base and coupling. ICAO Annex 14 requires elevated lights to be frangible and low enough to clear aircraft propellers and engine pods, and FAA specifications also set height limits by fixture type. Check the finished height and the break point of the full assembly before use. Keep the break point where the fixture manufacturer's assembly drawing places it (normally the frangible coupling near the base), and do not add rigid length or mass above it unless the manufacturer approves.
Material & Finish
Resistance to Corrosion and Environmental Exposure
Material and Finish
Material selection depends on the application and environmental conditions. Protective coatings or finishes may be specified where required for resistance to corrosion and environmental exposure.
The selected finish should be compatible with the surrounding airfield environment and connected mounting components.
Installation
Installation Considerations
Installation Should Confirm
- Correct extension length
- Correct diameter and interface
- Compatibility with the mounting stem and base
- Compatibility with the fixture or frangible coupling
- Required finished fixture elevation
- Correct alignment and, for directional lights, the original aiming
- Secondary cable length and routing through the stem
- Secure mechanical engagement
- Appropriate installation and tightening procedure
Avoid any field modification that could compromise the mechanical performance or compatibility of the extension stem.
Replacement & Retrofit
Refurbishment Where Mounting Height Must Change
Retrofit Use
Extension stems can be useful in airfield lighting refurbishment where an existing fixture requires a revised mounting height. They may provide a practical alternative to replacing the complete base or support arrangement when the existing infrastructure remains suitable.
Check existing fixture dimensions, mounting interfaces and installed elevations before selecting a replacement extension stem.
Inspection & Maintenance
Routine Inspection
Check Extension Stems For
- Corrosion or coating deterioration
- Mechanical damage
- Loose connections
- Thread or interface damage
- Misalignment
- Cracks near thread roots or the coupling joint
- Signs of unauthorised modification
- Evidence of excessive movement or mechanical deterioration
Assess damaged components and replace them where their condition could affect fixture support or alignment.
Standards & Project Requirements
Follow the Applicable Equipment and Project Requirements
Requirements
Extension stem selection and installation should follow the applicable airfield lighting equipment, mounting and project requirements. Confirm length, structural characteristics, material and interface for the specific fixture and installation arrangement.
Where the extension forms part of a frangible mounting assembly, review the complete assembly to ensure compatibility with the applicable requirements.
References: ICAO Annex 14 Vol. I, Chapter 5 (elevated lights frangible and low enough to clear propellers and engine pods), ICAO Doc 9157 Part 4, FAA AC 150/5345-42K (light bases, transformer housings and accessories), AC 150/5345-45C (low-impact-resistant structures) and AC 150/5345-46F (light fixtures) as applicable, and the fixture manufacturer instructions. Verify the current edition of each.
FAQ
AGL Extension Stem — Frequently Asked Questions
What is an AGL extension stem?
An extension stem provides additional mounting height or dimensional adjustment for compatible elevated airfield lighting fixtures. It lets the installed elevation of an elevated fixture be adjusted while keeping a suitable mechanical interface between the fixture, mounting stem, base and associated mounting hardware. It is considered together with the mounting stem, base, fixture and any intermediate coupling so that the complete assembly is compatible.
When is an extension stem used?
It is used to increase mounting height, adjust the installed elevation of elevated airfield lights, provide dimensional clearance between a fixture and its base, adapt existing mounting arrangements during refurbishment and support selected replacement projects. It can also be integrated with compatible mounting stems and frangible couplings.
How is the extension length selected?
The primary purpose is to give additional elevation where the standard mounting arrangement does not provide the required fixture height. Select the length from the finished installation level, the fixture requirements and the complete mounting configuration, and avoid excessive or unnecessary extension where it could affect the mechanical characteristics of the assembly.
What interface and compatibility checks are needed?
The stem is installed between compatible mounting components and must provide the correct mechanical interface at both ends. Confirm the thread type, diameter, connection geometry and overall length before procurement, and check it together with the mounting stem, base, fixture and any intermediate coupling. A longer stem also needs enough secondary cable, which should be routed with the connector inside the stem so they are not strained, pinched or bent below the cable bend radius.
Does a longer extension stem affect frangibility and height limits?
Adding length raises the fixture and increases the bending load on the base and coupling. ICAO Annex 14 requires elevated lights to be frangible and low enough to clear aircraft propellers and engine pods, and FAA specifications also set height limits by fixture type. Check the finished height and the break point of the full assembly before use. Keep the break point where the fixture manufacturer’s assembly drawing places it, normally the frangible coupling near the base, and do not add rigid length or mass above it unless the manufacturer approves.
Can an extension stem be used with a frangible coupling?
Where an elevated fixture needs a frangible mounting arrangement, the extension stem may be coordinated with a compatible frangible coupling, and the complete fixture, coupling, extension and support assembly should be checked for interface compatibility. The stem should not be modified in a way that could alter the intended mechanical or frangible characteristics of the complete mounting arrangement.
What are extension stems made of, and how is the finish chosen?
Material depends on the application and environmental conditions, and protective coatings or finishes may be specified for resistance to corrosion and environmental exposure. The finish should suit the surrounding airfield environment and the connected mounting components. Structural suitability depends on the stem’s material, diameter, length, geometry, connected equipment and installation configuration, so it should be selected according to the fixture and support conditions rather than by length alone.
What should be checked during installation?
Confirm the correct extension length, diameter and interface, compatibility with the mounting stem, base and fixture or frangible coupling, the required finished fixture elevation, correct alignment and, for directional lights, the original aiming. Also confirm the secondary cable length and routing through the stem, secure mechanical engagement and an appropriate installation and tightening procedure. Avoid any field modification that could compromise the mechanical performance or compatibility of the stem.
Can an extension stem be used in refurbishment?
Yes. Extension stems can be useful in refurbishment where an existing fixture needs a revised mounting height. They may be a practical alternative to replacing the complete base or support arrangement when the existing infrastructure remains suitable. Check the existing fixture dimensions, mounting interfaces and installed elevations before selecting a replacement stem.
How should extension stems be inspected?
Check for corrosion or coating deterioration, mechanical damage, loose connections, thread or interface damage, misalignment, cracks near thread roots or the coupling joint, signs of unauthorised modification, and evidence of excessive movement or mechanical deterioration. Damaged components should be assessed and replaced where their condition could affect fixture support or alignment.
Which standards apply to extension stems?
Selection and installation should follow the applicable airfield lighting equipment, mounting and project requirements. References include ICAO Annex 14 Vol. I Chapter 5, ICAO Doc 9157 Part 4, FAA AC 150/5345-42K on light bases, transformer housings and accessories, AC 150/5345-45C on low-impact-resistant structures and AC 150/5345-46F on light fixtures as applicable, and the fixture manufacturer’s instructions. Verify the current edition of each, and confirm length, structural characteristics, material and interface for the specific fixture and installation.
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 Stem Length & Fixture Compatibility
Precision AGL Solutions can support extension stem selection based on the required additional height, fixture type, mounting interface, material and complete support configuration.
- Emailprecisionaglsolutions@gmail.com
- Websiterahulsharmaagl.in
- LinkedInPrecision AGL Solutions
- Phone+91 98214 96412
Engineering Note
Length, structural characteristics, material and interface should be confirmed for the specific fixture and installation arrangement. Where the extension forms part of a frangible mounting assembly, review the complete assembly to ensure compatibility with the applicable requirements.
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.