FAA AC 150/5345-27F Wind Cone Requirements: What US Airport Operators Need to Know
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Why FAA AC 150/5345-27F matters to US airport operators
If you operate or maintain a public-use airport in the United States, your wind cone installation is not a matter of opinion. It is governed by Federal Aviation Administration Advisory Circular AC 150/5345-27F, which sets the specification for wind cone assemblies used at federally obligated airports and any facility receiving Airport Improvement Program (AIP) funding.
This guide walks procurement managers, airport operations leads and safety officers through what AC 150/5345-27F actually requires. We cover size classes, fabric and frame construction, lighting, frangibility, siting and inspection. We also flag where the FAA standard diverges from ICAO Annex 14 and CAA CAP 168, in case you operate a facility that needs to satisfy more than one framework.
Falcon manufactures wind cones in the United Kingdom and ships worldwide free of charge, with duties and import taxes covered (DDP). US buyers receive the product ready to install with no customs paperwork to chase.
What AC 150/5345-27F covers
FAA Advisory Circular AC 150/5345-27F is the current revision of the federal specification for airport wind cone assemblies. It defines the equipment itself, not the siting rules (those sit in AC 150/5300-13, the Airport Design circular) and not the lighting circuit rules (those sit in AC 150/5340-30, the Design and Installation Details circular).
The 27F document specifies:
- Wind cone size and shape
- Fabric material, colour and construction
- Frame and bearing assembly
- Lighting for night operations
- Frangible coupling requirements
- Electrical and environmental performance
- Marking and identification
If a wind cone assembly is procured using federal funds, or installed at a Part 139 certificated airport, it must meet this specification. Non-federally funded general aviation airports are strongly encouraged to follow it, and most state aeronautics divisions require it.
Size classes: L-806 and L-807
AC 150/5345-27F defines two wind cone size classes, identified by their L-code.
L-807 (Size 1 and Size 2)
The L-807 is the externally lit or unlit wind cone assembly. It comes in two sizes:
- Size 1: 8 ft (2.4 m) long, 18 in (0.46 m) throat diameter
- Size 2: 12 ft (3.6 m) long, 36 in (0.91 m) throat diameter
Size 2 is the standard for primary wind direction indicators at most towered airports. Size 1 is permitted at smaller general aviation fields and as supplemental indicators at runway thresholds.
L-806 (internally lit, Size 2 only)
The L-806 is the internally illuminated 12 ft wind cone, used where external floodlighting is impractical or where the wind cone serves as both indicator and approach reference at night.
The cone must fully extend in a 15-knot (17 mph / 28 km/h) wind and indicate true wind direction within ±5 degrees in winds of 3 knots or greater.
Specification summary table
| Requirement | L-807 Size 1 | L-807 Size 2 | L-806 (internally lit) |
|---|---|---|---|
| Length | 8 ft (2.4 m) | 12 ft (3.6 m) | 12 ft (3.6 m) |
| Throat diameter | 18 in (0.46 m) | 36 in (0.91 m) | 36 in (0.91 m) |
| Full extension wind speed | 15 kt | 15 kt | 15 kt |
| Directional accuracy | ±5° at ≥3 kt | ±5° at ≥3 kt | ±5° at ≥3 kt |
| Fabric colour | Aviation orange or white | Aviation orange or white | Aviation orange or white |
| Lighting | External (optional) | External (optional) | Internal (required) |
| Frangible coupling | Required | Required | Required |
| Bearing | Sealed, low-friction | Sealed, low-friction | Sealed, low-friction |
| Service temperature | -67°F to +131°F | -67°F to +131°F | -67°F to +131°F |
Fabric, colour and visibility
The specification requires the cone fabric to be aviation orange. White is permitted only where it provides greater contrast against the operational background, which is rare. The fabric must be a high-tenacity woven synthetic with documented tear and UV resistance.
Falcon Premium wind cones are manufactured from a heavyweight polyamide with reinforced seams and a UV-stabilised dye to maintain colour saturation through the service life. Fading reduces visibility and is one of the most common reasons for premature replacement. For more on judging when a cone has reached the end of its service life, see /blogs/guides/windsock-replacement.
The cone is sewn with tapered panels so it inflates progressively. Below the rated full-extension wind speed it deflects to indicate lower wind velocities. The taper is not cosmetic. It is the mechanism by which pilots read approximate speed from the cone angle.
Frame, bearing and pole
AC 150/5345-27F requires the wind cone to rotate freely on a sealed bearing assembly. Friction in the bearing causes lag and reduces directional accuracy in light winds, which is precisely when pilots most need a reliable reference.
The supporting pole must include a frangible coupling. This is a deliberate weak point in the structure, typically positioned within 12 inches (300 mm) of grade, designed to break cleanly on impact from an aircraft strike. Frangibility is a non-negotiable requirement at any wind cone sited within an airport's runway or taxiway safety areas, as defined in AC 150/5300-13.
Mounting hardware must withstand the structural wind loads specified in the circular while still releasing at the frangible point under aircraft impact. Falcon supplies a compatible /products/falcon-swivel-arm for installations where pole-top mounting is preferred over a fixed mast head.
Lighting requirements
For airports with night operations, the wind cone must be lit. AC 150/5345-27F permits two approaches:
External lighting (L-807): Floodlights mounted on the pole or adjacent structures, illuminating the cone from outside. The light must be positioned to avoid glare into the cockpit on approach and must achieve a minimum average illuminance on the cone surface as defined in the circular.
Internal lighting (L-806): A lamp assembly inside the throat of the cone, illuminating the fabric from within. This produces an evenly lit cone visible from all approach angles and is preferred where pole-mounted floodlights would create obstructions.
LED retrofits are now standard. The circular permits LED light sources provided they meet the photometric, chromaticity and reliability criteria. The fitting must withstand the same temperature and vibration environment as the rest of the assembly.
Siting on the airfield
While AC 150/5345-27F specifies the equipment, siting comes from AC 150/5300-13 (Airport Design). The headline rules:
- The primary wind cone must be visible from the approach end of every runway and from the airport's traffic pattern.
- It must be sited clear of runway and taxiway safety areas, or installed on a frangible mount if it cannot be.
- Supplemental wind cones may be installed near runway thresholds at larger fields.
- The cone must be free from turbulence from buildings, trees or terrain that would cause it to misread local wind.
- A segmented circle around the primary wind cone is required at non-towered airports without a control tower.
For a wider discussion of how to size and site cones across different facility types, see /blogs/guides/windsock-size-guide and /blogs/guides/windsock-installation-guide.
Inspection, maintenance and replacement
Part 139 certificated airports must inspect wind cones as part of the daily self-inspection programme required under 14 CFR Part 139.327. The inspection covers:
- Fabric condition (tears, fading, contamination)
- Free rotation of the bearing
- Lighting function
- Frangible coupling integrity
- Pole verticality and structural condition
There is no federally mandated replacement interval. Replacement is condition-based. In practice, a quality aviation-grade cone in continuous outdoor service in the continental US lasts between 12 and 24 months, depending on UV exposure and prevailing wind energy. Coastal and desert installations sit at the shorter end of that range.
How FAA differs from ICAO and CAA
If you operate facilities under more than one regulatory framework, the differences matter at procurement stage.
| Parameter | FAA AC 150/5345-27F | ICAO Annex 14 | CAA CAP 168 |
|---|---|---|---|
| Minimum length (primary) | 12 ft (3.6 m) | 3.6 m | 3.6 m |
| Throat diameter | 36 in (0.91 m) | 0.9 m | 0.9 m |
| Full extension wind | 15 kt | 15 kt (28 km/h) | 15 kt |
| Colour | Orange or white | Single colour, or 5 alternating bands | Single colour, or 5 alternating bands |
| Lighting | Internal or external | Required at night use | Required at night use |
| Frangibility | Required in safety areas | Required | Required |
The dimensional requirements are essentially harmonised. The most visible difference is colour: ICAO and CAA permit (and at some airports require) the five-band alternating pattern, while FAA standardises on solid aviation orange. For a fuller comparison, see /blogs/guides/windsock-compliance-standards.
Procurement checklist for US airport operators
Before raising a purchase order, confirm:
- Size class (L-807 Size 1, L-807 Size 2, or L-806)
- Mounting method (snap-on for quick changeover, lace-on for permanent installations)
- Lighting requirement and voltage
- Frangible coupling specification matched to your pole
- Fabric warranty and stated service life
- Documentation of compliance with AC 150/5345-27F on supplier's letterhead
Falcon supplies all of the above as standard with every order, with the compliance documentation issued at point of dispatch.
Frequently asked questions
What is FAA AC 150/5345-27F?
FAA Advisory Circular AC 150/5345-27F is the federal specification for airport wind cone assemblies in the United States. It defines size, fabric, frame, bearing, lighting and frangibility requirements for L-806 and L-807 wind cones used at federally funded and Part 139 certificated airports.
What is the difference between L-806 and L-807 wind cones?
L-806 is a 12-foot internally illuminated wind cone. L-807 is an externally lit or unlit wind cone, available in 8-foot (Size 1) and 12-foot (Size 2) versions. L-806 is used where internal illumination is preferred for night operations.
Does my general aviation airport have to comply with AC 150/5345-27F?
If your airport receives Airport Improvement Program funding or holds Part 139 certification, compliance is mandatory. Non-federally obligated general aviation airports are not legally required to comply, but most state aeronautics divisions and insurers expect it, and following the circular is best practice.
How often should an FAA-compliant wind cone be replaced?
There is no fixed replacement interval. Replacement is condition-based, driven by fading, fabric damage, bearing wear or coupling deterioration. Typical service life in continuous outdoor use in the US is 12 to 24 months.
What colour does the FAA require for wind cones?
AC 150/5345-27F specifies aviation orange as the standard colour. White is permitted only where it provides better contrast against the operational background. Unlike ICAO and CAA standards, the FAA does not use the alternating five-band pattern.
Are frangible couplings mandatory?
Frangible couplings are mandatory for any wind cone installed within a runway or taxiway safety area as defined in AC 150/5300-13. They are best practice for all airfield wind cones regardless of siting.
Can I import an FAA-compliant wind cone from a UK manufacturer?
Yes. Falcon manufactures wind cones in the United Kingdom to FAA AC 150/5345-27F specification and ships to US airports free of charge with duties and import taxes covered (DDP). Compliance documentation is issued with every order.
The Falcon Premium range
The Falcon Premium is manufactured in the United Kingdom in 4FT, 7FT and 12FT lengths, available in snap-on or lace-on fixings. The 12FT Premium meets the dimensional, fabric and construction requirements of FAA AC 150/5345-27F for L-807 Size 2 wind cones. UV-stabilised aviation orange fabric, reinforced taper-sewn panels and sealed bearing compatibility come as standard.
To confirm specification for your airfield, or to request a compliance letter for your procurement file, view the /products/falcon-premium-snap-on-windsock or /products/falcon-premium-lace-on-windsock and contact the Falcon team. Free worldwide shipping. Duties and import taxes covered. No customs paperwork on your side.