PAPI Installation Hardware
PAPI Mounting Stand & Frangible Coupling for Airfield Ground Lighting
The structural interface between the PAPI light unit and the airfield
PAPI mounting hardware supports accurate positioning, stable aiming, maintainable access and repeatable alignment throughout the operational life of the system. Where required, frangible coupling arrangements provide a controlled structural interface to the foundation or support structure.
Supplied by Precision AGL Solutions
Product Overview
PAPI Mounting Stand & Frangible Coupling
What It Is
Precision AGL Solutions supplies PAPI mounting stands and associated hardware for new installations, replacement works and maintenance. A stand typically provides a rigid support that holds the light unit at its specified position while allowing the mechanical adjustments needed for commissioning and alignment.
Select the mounting system as part of the complete PAPI installation, considering height, longitudinal and lateral position, vertical adjustment, azimuth alignment, foundation interface, maintenance access and any frangibility requirements.
The Arrangement May Include
- PAPI mounting stand or support frame
- Equipment mounting brackets and adjustable interfaces
- Base plates, anchor bolts and foundation hardware
- Levelling and height adjustment
- Horizontal alignment and vertical aiming interface
- Mechanical locking hardware
- Protective fasteners and fixings
- Frangible coupling / breakaway interface where specified
- Maintenance-access provisions
The exact configuration depends on the PAPI manufacturer, light-unit construction, installation geometry and project requirements.
Applications
Where PAPI Mounting Hardware Is Used
PAPI system installationsMechanical interface between each light unit and the prepared foundation.
New airport constructionIncorporated in civil, electrical and visual-aid coordination.
Runway rehabilitationReplacement or upgrade during visual-aid modernization.
PAPI replacementWhere supports are damaged, corroded, incompatible or lack adjustment.
Maintenance & corrective worksRepair, realignment and component replacement without full replacement.
Why the Mounting Arrangement Matters
Mechanical Mounting Affects PAPI Performance
A Suitable Arrangement Provides
- Stable support for the light unit
- Controlled installation height
- Accurate positioning relative to the runway
- Adequate adjustment for commissioning
- Secure locking after alignment
- Resistance to operational vibration
- Environmental durability
- Access for inspection and maintenance
- Compatibility with the PAPI manufacturer's equipment
- Appropriate foundation attachment
- Compatibility with any frangibility requirements
The Risk
The light unit must remain in a precisely defined position and orientation to provide the intended visual approach guidance. A mechanically unstable or poorly configured assembly can introduce movement, misalignment or difficulty during periodic inspection.
PAPI Mounting Stand Design
Structural Support, Equipment and Foundation Interfaces
Structural Support
The stand provides the primary mechanical support and should be sufficiently rigid while remaining compatible with the structural and frangibility requirements of the project. It may use a vertical support, base plate, equipment bracket or fabricated frame.
Equipment Interface
- Mounting-hole pattern, spacing and fastener size
- Bracket geometry
- Equipment mounting height
- Adjustment range and access
- Locking arrangement
- Overall equipment envelope
Verify against the current PAPI equipment drawing before procurement.
Foundation Interface
- Anchor bolts
- Embedded threaded components
- Base plates and stud assemblies
- Concrete foundation interfaces
- Dedicated brackets
- Project-specific support structures
Coordinate dimensions and fixings with civil works before installation.
PAPI Mounting Adjustment
Positioned Accurately During Commissioning
The available adjustment range is manufacturer-specific; confirm it from the applicable equipment drawing.
| Adjustment | Purpose |
|---|---|
| Vertical adjustment | Establish required equipment elevation and accommodate installation tolerances |
| Horizontal / azimuth adjustment | Establish required orientation relative to the runway centreline |
| Levelling adjustment | Compensate for small foundation or installation tolerances |
| Mechanical locking | Securely lock the established position to minimize unintended movement |
Frangible Coupling
A Controlled, Predictable Breakaway Interface
What It Is
A frangible coupling is a mechanically controlled interface giving a predictable structural separation or breakaway characteristic as required by the applicable airfield installation design. Frangibility requirements concern reducing the hazard presented by certain structures or equipment supports in the event of an aircraft or vehicle impact.
PAPI light units stand in the runway strip and must be frangible under ICAO Annex 14 and FAA requirements, so the coupling is normally part of each mounting leg. Do not assume every PAPI uses an identical coupling; select and install the one approved for the equipment model as part of its structural configuration.
Typical Arrangement
PAPI Light Unit
Mounting Bracket
Support Stand
Frangible Coupling
Foundation / Interface
The actual arrangement varies with equipment design and project requirements.
Frangible Coupling Considerations
What Must Be Coordinated
Important Considerations
- Mechanical load requirements and equipment weight
- Mounting geometry and coupling dimensions
- Connection hardware
- Breakaway characteristics
- Structural interface
- Corrosion protection
- Installation orientation
- Maintenance accessibility
- Compatibility with the PAPI manufacturer's mounting arrangement
Do Not Substitute
Do not replace the coupling with an unrelated mechanical breakaway component without confirming compatibility with the complete installation design.
FAA AC 150/5345-28H Mounting Requirements
What the FAA Equipment Standard Requires of the Mounting
Mounting Legs
- At least three adjustable legs for levelling, or two legs if equivalent rigidity and levelling capability are demonstrated
- Levelling must cope with one side of the unit being up to 1 in (25 mm) higher or lower than the other
- Each leg includes the housing mounting and level-adjusting hardware, a frangible coupling to FAA drawing C-6046 (or an equivalent part that passes the frangibility test) and a flange for a concrete pad
- The installer supplies the 2-inch electrical metallic tubing
Limits and Qualification Tests
- Light unit not higher than 40 in (1 m) at its minimum mounting height
- Weight not more than 100 lb (45 kg) per light unit, or 150 lb (68 kg) with an integral power and control unit
- Adjusting hardware vibration-resistant, so the optical system cannot move
- Frangibility of the legs equal to the 2-inch coupling of drawing C-6046, per AC 150/5220-23A
- Rigidity: after a 15 lb/ft² static load for 5 hours the beam pattern must stay within ¼ in (6 mm) at 20 ft (6 m)
- Wind: 100 mph (161 km/h) without displacing the pattern beyond the rigidity limit
These are equipment-qualification requirements. Your PAPI manufacturer's drawings and the approved project design set the actual mounting dimensions, coupling and breakaway height.
Installation Considerations
Position, Elevation and Centreline Relationship
PAPI Position
The stand must allow installation at the specified location relative to the runway and threshold, established from the approved airfield layout and PAPI siting documentation.
Mounting Elevation
- Foundation elevation and finished ground level
- Equipment mounting height
- Required optical reference height
- Adjustment allowance
- Local grading and drainage
Verify the final elevation against the approved PAPI design.
Runway Centreline Relationship
- Runway centreline and threshold location
- PAPI baseline
- Intended approach path
- Published approach geometry where applicable
- Obstacle-clearance requirements
PAPI Alignment and Mounting
Works Together With Alignment Equipment
Dedicated equipment such as a PAPI Alignment Telescope / Aiming Device may be used where required by the equipment and project procedure.
- Prepare and inspect the foundation
- Install the mounting stand
- Check the mounting position
- Install the PAPI light unit
- Establish the required horizontal orientation
- Establish the required vertical aiming angle
- Check the optical reference
- Tighten and lock adjustment hardware
- Verify the final position
- Record installation and alignment measurements
Mechanical Stability
Critical After Alignment Is Complete
The Arrangement Should Minimize
- Vibration-induced movement
- Loosening of fasteners
- Rotation of the equipment
- Settlement-related displacement
- Bracket deformation
- Uncontrolled changes in aiming position
After Final Alignment
Check all locking and fixing components in accordance with the equipment manufacturer's installation instructions.
Verification
Alignment Is Verified After Mounting, Not Assumed
After Installation or Re-aiming
The stand must hold the unit level and locked so the aiming angle does not drift. After installation, and after any impact, foundation work or re-aiming, verify the angular setting with approved instruments and record it. A new or relocated PAPI is also subject to flight inspection under the authority's requirements.
Frangibility
PAPI units must be frangible and mounted as low as their function allows (Annex 14, Vol. I, Chapters 5 and 9). FAA practice puts the breakaway point at or just above grade. The PAPI manufacturer's coupling drawing and the approved design set the exact point, so do not substitute a coupling.
Materials & Environmental Protection
Exposed Airfield Environments
Exposure
- Rain, humidity and UV
- Temperature cycling
- Dust and sand
- Runway contaminants
- De-icing chemicals where applicable
- Coastal or salt-laden atmosphere
Possible Construction / Protection
- Stainless steel components
- Corrosion-resistant alloys
- Protected carbon-steel fabrication
- Protective coatings
- Galvanized components
- Corrosion-resistant fasteners
Confirm the material specification against the current product drawing and project requirements.
Technical Data
Parameters to Confirm for the Specific Configuration
Take exact dimensions, material grades, fixing details, adjustment ranges and coupling characteristics from the current manufacturer drawing and approved project documentation before procurement.
| Parameter | Typical / Required Information |
|---|---|
| Product type | PAPI mounting stand / support assembly |
| Application | PAPI visual approach slope indicator installation |
| Equipment compatibility | Specific PAPI light-unit model |
| Mounting dimensions | Manufacturer / project specific |
| Mounting-hole pattern | Manufacturer / project specific |
| Equipment interface | Dedicated PAPI mounting bracket / interface |
| Foundation interface | Base plate, anchor bolts or project-specific arrangement |
| Material | Corrosion-resistant or protected structural material |
| Surface protection | Manufacturer / project specific |
| Vertical adjustment | According to mounting design |
| Horizontal adjustment | According to mounting design |
| Locking arrangement | Mechanical locking hardware |
| Frangible coupling | Part of the PAPI mounting leg; required for frangibility (ICAO Annex 14, FAA AC 150/5345-28H). Confirm the approved type |
| Coupling dimensions | Manufacturer / project specific |
| Coupling characteristics | Project and approved equipment configuration specific |
| Fasteners | Equipment / project specific |
| Operating environment | Outdoor airfield environment |
| Maintenance access | Designed for inspection and adjustment |
| Installation method | Foundation-mounted / project-specific |
| Overall dimensions / weight | Manufacturer drawing / specific |
| Foundation requirements | Project-specific |
| Documentation | Installation drawing, datasheet and compatibility information |
Mounting Compatibility
Verify Before Selecting a Replacement Stand
PAPI Equipment
- Manufacturer and model
- Number of light units
- Mechanical mounting arrangement
- Existing support configuration
Foundation
- Existing dimensions
- Anchor-bolt arrangement
- Finished surface elevation
- Foundation condition
- Available fixing points
Alignment
- Required installation position
- Equipment height
- Horizontal orientation
- Vertical aiming adjustment
- Available adjustment range
Frangibility
- Whether a frangible arrangement is required
- Approved coupling type and location
- Structural interface
- Applicable project requirements
New Installation Workflow
From Layout Review to Verification
- Review the PAPI layout — location, orientation and geometry
- Confirm equipment interface — mounting pattern of the light units
- Coordinate the foundation — dimensions, anchors, finished elevation
- Select the mounting stand — adjustment and fixing provisions
- Determine frangible requirements — confirm and select the approved arrangement
- Install the stand — per approved documentation
- Install PAPI units — initial mechanical positioning
- Align the system — orientation and aiming geometry
- Lock the assembly — all adjustment and fixing points
- Complete verification — inspect and document the configuration
Replacement & Retrofit Applications
Survey Before Selecting Replacement Hardware
Reasons for Replacement
- Corrosion
- Impact damage and deformation
- Foundation modifications
- Obsolete equipment
- Replacement PAPI light units
- Damaged mounting brackets
- Loss of adjustment capability
- Fastener deterioration
- Changes to the airfield configuration
Do Not Select on External Dimensions Alone
Survey the existing foundation and mounting arrangement first. Check the equipment interface, foundation fixing pattern and required adjustment geometry.
Inspection & Maintenance
Structural Condition and Alignment Stability
Visual Inspection
- Corrosion
- Cracked or damaged components
- Bent brackets
- Loose fasteners
- Coating deterioration
- Foundation damage
- Evidence of impact
- Coupling damage
- Missing hardware
Mechanical Inspection
- Fastener security
- Mounting stability
- Adjustment mechanism condition
- Locking mechanism condition
- Foundation attachment
- Equipment movement
Where permitted by the manufacturer's maintenance procedure.
Alignment Verification
After impact, foundation work or significant mechanical intervention, check the PAPI alignment using the appropriate procedure and equipment.
Frangible Coupling Inspection
Confirm It Remains in Its Intended Condition
Check For
- Visible deformation
- Cracks
- Corrosion
- Damaged threads
- Incorrect fasteners
- Unauthorized modifications
- Evidence of impact
- Improper replacement components
After an Impact
A coupling that has experienced an impact or has visible structural damage should be evaluated according to the applicable manufacturer and project procedures before the PAPI is returned to service.
Common Installation Problems
Causes and Recommended Actions
| Problem | Possible Causes | Recommended Action |
|---|---|---|
| PAPI unit cannot be aligned | Incorrect bracket; insufficient adjustment range; incorrect foundation position; damaged adjustment hardware; incorrect dimensions | Verify the mounting interface and equipment drawing before modifying the support |
| Assembly moves after alignment | Loose fixings; inadequate locking; foundation movement; damaged bracket; structural deformation | Inspect the complete path from foundation to unit; repeat alignment verification after corrective work |
| Replacement PAPI does not match existing stand | Different hole pattern, equipment dimensions, support geometry, legacy hardware or installation height | Confirm using current equipment and mounting drawings, not visual similarity |
| Frangible coupling does not match installation | Incorrect model; different foundation interface; legacy equipment; project-specific structural arrangement | Confirm the approved coupling and structural interface before replacement |
Procurement Checklist
Provide as Much of the Following as Possible
This helps ensure the supplied assembly is compatible with the complete PAPI installation.
- PAPI manufacturer
- PAPI model
- Number of light units
- New installation or replacement
- Existing mounting stand details
- Foundation dimensions
- Anchor-bolt arrangement
- Required mounting height
- Project location / environment
- Frangible coupling requirement
- Existing coupling details
- Required quantity
- Applicable airport specification
- Applicable civil / structural requirements
Standards & References
Evaluate Against the Complete PAPI Installation
References
- ICAO Annex 14, Vol. I: PAPI (Chapter 5) and siting and frangibility of equipment (Chapter 9)
- ICAO Doc 9157 Part 4: visual aids
- FAA AC 150/5345-28H: PAPI equipment standard, including mounting legs, frangible couplings, height, rigidity and wind loading
- FAA AC 150/5220-23A: frangible connections, and FAA drawing C-6046 for the frangible coupling
- FAA AC 150/5345-45C: low-impact resistant (LIR) structures, used for approach-light and similar support structures rather than PAPI legs
- FAA AC 150/5340-30J: design and installation details for airport visual aids
- PAPI manufacturer installation instructions and approved foundation drawings
Applying Them
Evaluate the hardware against the complete PAPI installation, not a generic mounting specification. Where national or airport requirements set project-specific rules, they take precedence. Confirm current editions before procurement.
Engineering Documentation
Documents That May Be Requested
For replacement projects, photographs and measurements of the existing mounting arrangement help determine the correct configuration.
- PAPI mounting stand datasheet
- General arrangement drawing
- Mounting-hole drawing
- Foundation interface drawing
- Installation instructions
- Adjustment-range information
- Material specification
- Surface-treatment information
- Fastener specification
- Frangible coupling documentation, where applicable
- Equipment compatibility statement
- Maintenance instructions
- Inspection procedure
- Product photographs or dimensional drawings
Integration With the PAPI System
Civil, Mechanical, Electrical and Visual-Aid Coordination
Typical Installation
PAPI Light Units
Mounting Brackets / Stands
Foundation / Frangible Interface
Electrical Supply & Control
Works Together With
- PAPI alignment equipment
- Electrical cabling and isolating transformers
- Constant-current regulator
- Foundation and drainage
- Airfield pavement or groundworks
- Approach and runway geometry
Successful commissioning depends on coordination between all disciplines.
Recommended PAPI Installation Toolkit
A Coordinated Equipment Package
PAPI SystemPrimary visual approach slope indicator equipment.
PAPI Mounting StandMechanical support and installation interface.
Frangible CouplingWhere required by the approved installation configuration.
Alignment Telescope / Aiming DeviceField alignment and verification of PAPI aiming geometry.
Digital InclinometerSupporting angular measurement where appropriate.
PAPI Check StickPhysical reference / checking aid for installation and inspection.
Precision AGL Solutions Support
Selection of Compatible Mounting Hardware
We Assist With
- New PAPI installations
- Existing runway upgrades
- PAPI replacement projects
- Airfield rehabilitation
- Maintenance programs
- Mounting-system refurbishment
- Frangible-interface requirements
- Equipment compatibility review
For Replacement Projects
Technical evaluation can be based on the existing PAPI model, mounting dimensions, foundation arrangement and available project documentation.
FAQ
PAPI Mounting Stand & Frangible Coupling — Frequently Asked Questions
What is a PAPI mounting stand?
A PAPI mounting stand is a rigid support that holds the light unit at its specified position while allowing the mechanical adjustments needed for commissioning and alignment. The arrangement may include a support frame, equipment brackets, base plates and anchor bolts, levelling and height adjustment, horizontal alignment and vertical aiming interfaces, locking hardware and, where specified, a frangible coupling. The exact configuration depends on the PAPI manufacturer, light-unit construction and project requirements.
Why does the mounting arrangement matter for PAPI performance?
The light unit must remain in a precisely defined position and orientation to give the intended visual approach guidance. A mechanically unstable or poorly configured assembly can introduce movement, misalignment or difficulty during periodic inspection. A suitable arrangement gives stable support, controlled installation height, accurate positioning, adequate adjustment, secure locking, resistance to vibration, environmental durability and access for inspection and maintenance.
What is a frangible coupling and do PAPI units need one?
A frangible coupling is a mechanically controlled interface giving a predictable breakaway characteristic, reducing the hazard of an aircraft or vehicle impact. PAPI light units stand in the runway strip and must be frangible under ICAO Annex 14 and FAA requirements, so the coupling is normally part of each mounting leg. Do not assume every PAPI uses an identical coupling; select and install the one approved for the equipment model.
Where is the breakaway point of a PAPI mounting?
PAPI units must be frangible and mounted as low as their function allows (Annex 14, Vol. I, Chapters 5 and 9), and FAA practice puts the breakaway point at or just above grade. The PAPI manufacturer's coupling drawing and the approved design set the exact point, so do not substitute a coupling or replace it with an unrelated breakaway component without confirming compatibility with the complete installation design.
What does FAA AC 150/5345-28H require of PAPI mounting legs?
The standard calls for at least three adjustable legs for levelling, or two legs if equivalent rigidity and levelling capability are demonstrated, able to cope with one side of the unit being up to 1 in (25 mm) higher or lower than the other. Each leg includes the housing mounting and level-adjusting hardware, a frangible coupling to FAA drawing C-6046 (or an equivalent part that passes the frangibility test) and a flange for a concrete pad. The installer supplies the 2-inch electrical metallic tubing.
What height, weight and loading limits apply to FAA PAPI equipment?
The light unit must be no higher than 40 in (1 m) at its minimum mounting height and weigh no more than 100 lb (45 kg), or 150 lb (68 kg) with an integral power and control unit. Adjusting hardware must be vibration-resistant, and after a 15 lb/ft² static load for 5 hours the beam pattern must stay within ¼ in (6 mm) at 20 ft (6 m); the unit must also withstand 100 mph (161 km/h) wind. These are equipment-qualification requirements, and the manufacturer's drawings and approved project design set the actual dimensions.
What adjustments should a PAPI mounting stand provide?
Vertical adjustment sets the required equipment elevation and accommodates tolerances, horizontal or azimuth adjustment sets orientation relative to the runway centreline, levelling adjustment compensates for small foundation or installation tolerances, and mechanical locking secures the established position. The available adjustment range is manufacturer-specific, so confirm it from the applicable equipment drawing.
How is PAPI alignment verified after mounting?
The stand must hold the unit level and locked so the aiming angle does not drift. After installation, and after any impact, foundation work or re-aiming, verify the angular setting with approved instruments and record it. A new or relocated PAPI is also subject to flight inspection under the authority's requirements.
What should be checked before selecting a replacement PAPI stand?
Survey the existing foundation and mounting arrangement first, and do not select on external dimensions alone. Check the PAPI manufacturer and model, number of units, mounting-hole pattern and equipment interface, foundation dimensions, anchor-bolt arrangement and finished surface elevation, required equipment height, available adjustment range, and whether a frangible arrangement is required and which coupling type is approved.
How should the stand and frangible coupling be inspected?
Visually inspect for corrosion, cracked or damaged components, bent brackets, loose fasteners, coating deterioration, foundation damage, evidence of impact, coupling damage and missing hardware, and check fastener security, mounting stability, and the adjustment and locking mechanisms. For the coupling, look for deformation, cracks, corrosion, damaged threads, incorrect fasteners, unauthorised modifications and improper replacement components. A coupling that has experienced an impact or has visible structural damage should be evaluated under the manufacturer and project procedures before the PAPI is returned to service.
What information is needed to request PAPI mounting hardware?
Provide the PAPI manufacturer and model, number of light units, whether it is a new installation or replacement, existing mounting stand details, foundation dimensions, anchor-bolt arrangement, required mounting height, project location and environment, frangible coupling requirement and existing coupling details, required quantity, the applicable airport specification and civil or structural requirements. For replacement projects, photographs and measurements of the existing mounting arrangement help.
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 PAPI Mounting Hardware Details
For PAPI mounting stand and frangible coupling requirements, provide the PAPI equipment model, mounting dimensions, foundation arrangement and project requirements where available. Precision AGL Solutions can support selection of compatible mounting hardware for new installations, replacement projects and airfield maintenance applications.
- Emailprecisionaglsolutions@gmail.com
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- LinkedInPrecision AGL Solutions
- Phone+91 98214 96412
Engineering Note
PAPI mounting hardware is part of the complete visual approach slope indicator installation and should be selected according to the actual PAPI equipment, approved installation geometry, foundation design and applicable airfield requirements.
PAPI light units must be frangible. Verify the exact coupling type, dimensions and structural characteristics from the approved equipment and project documentation, and do not substitute the coupling.
Product dimensions, materials, adjustment ranges, fixing arrangements and frangible characteristics are manufacturer- and project-specific unless otherwise stated. Confirm the current technical datasheet and approved installation drawings 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.