+-----------------------------------+-----------------------------------+
| ![](media/image1.                 | **Advisory**                      |
| png){width="0.4791666666666667in" |                                   |
| height="0.47847222222222224in"}   | **Circular**                      |
|                                   |                                   |
| U.S. Department                   |                                   |
|                                   |                                   |
| of Transportation                 |                                   |
|                                   |                                   |
| **Federal Aviation**              |                                   |
|                                   |                                   |
| **Administration**                |                                   |
+-----------------------------------+-----------------------------------+

+------------------------------------+---------------+----------------+
| **Subject:** FAA SPECIFICATION FOR | **Date:**     | **AC No:**     |
| WIND CONE ASSEMBLIES               | 6/2/04        | 150/5345-27D   |
|                                    |               |                |
|                                    | **Initiated   | **Change:**    |
|                                    | by:** AAS-100 |                |
+------------------------------------+---------------+----------------+

**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_**

**1. PURPOSE.** This advisory circular (AC) contains a specification for
wind cone assemblies to be used to provide wind information to pilots of
aircraft.

**2. PRINCIPAL CHANGES.** The principal changes in this AC are:

a.  The equipment qualification requirements to be furnished under the
    Federal grant assistance program for airports has been revised.

b.  The new specifications for internally lighted wind cones have been
    added.

c.  Editorial changes have been made.

**3. CANCELLATION.** AC 150/5345-27C, Specification For Wind Cone
Assemblies, dated July 19, 1985, is canceled.

**4. APPLICATION.** The standards contained in this advisory circular
are recommended by the Federal Aviation Administration (FAA) in all
applications involving airport development of this nature. The
specification is an acceptable means for compliance with Federal
Aviation Regulation (FAR) Part 139 where such facilities may be
required. For airport projects receiving Federal grant-in-aid
assistance, the use of these standards is mandatory.

**5. METRIC UNITS.** To promote an orderly transition to metric units,
this specification includes both English and metric dimensions. The
metric conversions may not be exact equivalents and until there is an
official changeover to the metric system the English dimensions will
govern.

![](media/image2.png){width="2.5034722222222223in"
height="0.5847222222222223in"}

DAVID L. BENNETT

Director, Office of Airport Safety and Standards

**FAA SPECIFICATION FOR WIND CONE ASSEMBLIES**

**1. SCOPE AND CLASSIFICATION**.

**1.1 Scope.** This specification covers fabric windsocks and their
supporting structures used at airports and heliports to indicate surface
wind conditions.

**1.2 Wind Cone Assemblies Classification.**

**1.2.1 Types.**

L‑806 ‑ those mounted on low mass supporting structures

(typical assemblies are shown in figure 1)

L‑807 ‑ those mounted on rigid supporting structures

(typical assemblies are shown in figure 2)

**1.2.2 Styles.**

Style I-A -- externally lighted

Style I-B - internally lighted (typical internally lighted wind cone is
shown in figure 3)

Style II -- unlighted

**1.2.3 Sizes.**

Size 1 - 8 feet (2.5 m), for use with Type L‑806 and L‑807 assemblies.

Size 2 ‑ 12 feet (3.75 m), for use with Type L‑807 assemblies.

**2. REFERENCED DOCUMENTS.**

**2.1 General.** The following is a list of documents referenced in this
advisory circular.

**2.2 Federal Aviation Administration (FAA) Advisory Circulars.**

AC 150/5345‑43 Specification for Obstruction Lighting Equipment

AC 150/5345‑45 Lightweight Approach Light Structure

AC 150/5345-53 Airport Lighting Equipment Certification Program

**2.3 Federal Standard.**

FED‑STD 191A Textile Test Methods, or current version

(Copies of FAA advisory circulars may be downloaded from
[http://www.faa.gov/arp/150acs.cfm]{.underline})

**3. EQUIPMENT REQUIREMENTS**

**3.1 Environmental Conditions.** The wind cone assemblies must be
designed to operate under the following environmental conditions:

**a.** Temperature. Any ambient temperature between -67°F (‑55°C) and
131°F (+55°C.)

**b.** Wind. Wind speed up to 75 knots (140 km/hr or 86 mph).

**3.2 Fabric Windsocks.**

**3.2.1 Fabrication.** The fabric windsock must be made so it takes the
shape of a truncated cone when it is filled with air; be reinforced at
all points that are subject to abrasion by flexing against the metal
framework; and be designed to allow removal and replacement without the
use or special tools or stitching. The fabric windsock must be
constructed to allow water drainage out of the area of the basket
assembly.

**3.2.2 Dimensions.** The minimum effective length and the throat end
opening diameter of the fabric windsock are as follows:

**a. Size 1** ‑ Eight feet (2.5 m) in length and 18 inches (0.45 m) in
throat diameter.

**b. Size 2** ‑ Twelve feet (3.75 m) in length and 36 inches (0.9 m) in
throat diameter.

The taper or the fabric windsock from the throat to the trailing end
must be designed to cause the windsock to fully extend when exposed to a
wind of 15 knots (28 km/hr or 17 mph).

**3.2.3 Fabric.** Fabric for the windsock may be made of cotton, a
synthetic material, or a blend of the two, and may be coated. If the
fabric is not naturally immune to water absorption, it must be treated
to become water repellent. Color of the windsock fabric may be natural
(white), yellow, or orange. Color will be specified by the purchaser.
The manufacturer must certify that the fabric meets the following
requirements:

**a.** Minimum breaking strength: Warp ‑ 150 pounds (667 N); Filling ‑
150 pounds (667 N). The method 5102 of FED-STD-191A can be used to
determine the minimum breaking strength.

**b.** Good or better colorfastness as determined by Method 5671 of
FED‑STD‑191A.

**3.3 Framework.** A framework must be provided to hold the throat of
the fabric windsock fully open under no wind conditions and to provide
an interface with the support. It must be of low‑mass design so as to
offer minimum resistance to an inadvertent strike by aircraft. The
framework may be made of metallic or nonmetallic material. Ferrous
materials must be hot‑dipped galvanized, zinc plated, or epoxy‑resin
coated to provide protection against corrosion. The framework is to be
constructed so as to deter the accumulation of water in the windsock.
The framework must support the fabric windsock in a rigid position for
three‑eighths of its length. When the fabric windsock is attached to the
framework the combination must perform as a wind vane. Bearings,
bushings, or like devices must be either permanently lubricated or
provided with fittings to allow periodic lubrication.

**3.4 Supporting Structures.** Typical supporting structures are shown
in figures 1 through 3. Although the illustrations are typical, the
dimensions shown are to be complied with.

**3.4.1 Type L‑806.** The type L‑806 support must be of low‑mass, and
designed for easy installation and maintenance. When firmly anchored,
the frangible support must withstand a moment of 350 pound‑feet (475 N
m) without damage and fail before a moment of 700 pound‑feet (950 N m)
is reached by a force applied parallel to and 6 feet (1.8 m) above the
surface to which the support is attached. Alternatively, a support
meeting the requirements of AC 150/5345‑45, Lightweight Approach Light
Structure, may be used.

**3.4.2 Type L‑807.** The type L‑807 support may be hinged at its base
or near its middle so the wind cone and light fixture can be serviced
from the ground. When the support is mounted in place, it must
withstand, without damage, a moment of not less than 3200 pound‑feet
(4340 N m) when the force is applied parallel to and 16 feet (4.8‑m)
above the surface to which the support is attached. This support may be
used only where allowed by airport design standards published in AC
150/5300-13, Airport Design.

**3.5 Windsock Movement.** The windsock must move freely about the
vertical shaft it is attached to and when subjected to wind of 3 knots
(5.6 km/hr or 3.5 mph) or more and indicate the true wind direction
within +/- 5 degrees.

**3.6 Photometric requirements.** Light fixtures must be placed and
aimed to minimize objectionable glare to aircraft pilots. Wiring from
the base of the supporting structure to the light fixture must be housed
in the structure or in electrical conduit. Electrical cable must be of
proper type and size for its application.

**3.6.1** Style I-A, externally lighted wind cone assemblies must be
supplied with sufficient light fixtures to provide a minimum of 2
foot‑candles (fc)(21.5 lux) illumination on any point of the horizontal
plane described by the complete rotation of the upper surface of a fully
extended cone.

**3.6.2** Style I-B, internally lighted wind cone assemblies must be
size 2 and must have at least two (2) spotlights mounted internally
within the windsock throat section. Two separate lamps are used in the
assembly so that failure of a single lamp will not render the unit
ineffective at night. The power supply arrangement must be in such a way
that when transferring electrical power to the lamps the wind cone
assembly is allowed to rotate freely with the existing wind. The top and
lateral surfaces of the fabric windsock of style I-B wind cone
assemblies must have an average luminance of 10 to 30 ft-lamberts (fL)
and a minimum luminance at any point of 2 ft-lamberts (fL).

**3.7 Obstruction Light**. When required, an L‑810 obstruction light
conforming to AC 150/5345‑43, Specification for Obstruction Lighting
Equipment, must be supplied. The obstruction light is to be mounted at
the highest point of the wind cone assembly to avoid being obscured by
any other part when viewed from above.

**3.8 Painting.** All exposed metal parts of the wind cone assembly,
except reflecting surfaces of light fixtures, must be given one prime,
one body, and one finish coat of paint. The prime coat must be
appropriate for the particular metal being painted. The finish coat must
consist of a colorfast orange color paint.

**3.9 Equipment Parts and Instructional Manual.** A manual must be
supplied with each wind cone assembly containing, as a minimum, the
following information:

**a.** Complete wiring diagram for lighted wind cones.

**b.** Complete parts list with the name and part number of the original
manufacturer.

**c.** Assembly and installation instructions, including mounting
foundation and anchor bolt requirements.

**d.** Maintenance instructions.

**4. EQUIPMENT QUALIFICATION REQUIREMENTS.**

**4.1 Qualification Procedures.** Procedures for qualifying equipment to
be furnished under the federal grant assistance program for airports are
contained in Advisory Circular 150/5345-53, Airport Lighting Equipment
Certification Program.

**4.2 Qualification Tests.**

**4.2.1 General.** Each type, style, and size of wind cone assembly for
which approval is requested must be tested.

**4.2.2 Windsock Cone Attachment.** Test the attachment of the fabric
windsock to the metal framework by applying the following tension to the
free end of the wind cone:

**a.** Size 1 ‑ 45 pounds (200 N)

**b.** Size 2 - 100 pounds (450 N)

Any distress noted in the fabric windsock or the means of attachment
will be cause for rejection.

**4.2.3 Support Rigidity.** Mount the support on a surface to simulate
its normal field installation and apply the following forces to the
support. The force must be applied parallel to and at the specified
distance from the surface:

+------------------+-------------------+---------------+--------------+
| # Type           | # Force           |               | # Distance   |
+------------------+-------------------+---------------+--------------+
|                  | Hold              | Fail by       |              |
+------------------+-------------------+---------------+--------------+
| L-806            | 58 lb. (264 N)    | 117 lb. (530  | 6 ft. (1.8   |
|                  |                   | N) **1/**     | m)           |
+------------------+-------------------+---------------+--------------+
| L-807            | 200 lb. (890 N)   | \-            | 16 ft. (4.9  |
|                  |                   |               | m)           |
+------------------+-------------------+---------------+--------------+

**1/** Low mass structures must cause minimal damage when struck by
aircraft. The structure must not wrap around the aircraft but must
crumple or collapse on impact.

**4.2.4 Windsock Movement.** Test the windsock movement around the
vertical axis. The windsock must move freely and align with a 3-knot
(5.6 km/hr or 3.5 mph) wind as specified in paragraph 3.5. The wind test
must be run at no less than 6 equally spaced points about the vertical
axis.

**4.2.5** **Photometric Test**

**4.2.5.1** **Style I-A,** **Externally Lighted Wind Cone**. The
illumination must be tested at the throat, trailing end, and center
points of the upper surface of the extended fabric wind cone at
30-degree intervals throughout a complete horizontal rotation of the
wind cone. The illumination at the test points must not be less than 2
foot‑candles as noted in paragraph 3.6.1.

**4.2.5.2** **Style I-B,** **Internally Lighted Wind Cone**. The
internally lighted wind cone must be tested for luminance while fully
extended. Luminance measurements must be taken from 1 foot away from the
throat to 11 feet away from the throat at 1-foot intervals and 45-degree
increments around the circumference of the wind cone. The spot-size for
the luminance measurement must be 1.5 inches in diameter. The average
luminance on the top and lateral surfaces of the windsock must be
between 10 and 30 foot-lamberts as noted in paragraph 3.6.2.

6.  **Windsock Extension.** Test the windsock to assure that it extends
    fully when subjected to a wind of 15 (+2,‑1) knots (+3.7, ‑1.8)
    km/hr or (+2.3, -1.2 mph) ).

7.  **Windsock Fabric.** Supply a certification from the fabric
    manufacturer that the fabric meets the requirements in paragraph
    3.2.3. The manufacturer must retain on file written letters of
    conformance from the fabric manufacturer for all fabric used in the
    wind cone manufacture.

**5. PRODUCTION TEST REQUIREMENTS**

**5.1 Production Tests.** A certified copy of test reports on the tests
specified in paragraph 4.2.5, must be made available by the manufacturer
upon written request by the FAA.

![](media/image3.png){width="8.014583333333333in"
height="4.773611111111111in"}

Figure 1. Typical Type L-806 supports

## ![](media/image4.png){width="7.7034722222222225in" height="4.868055555555555in"}

## Figure 2. Typical Type L-807 supports 

![](media/image5.png){width="4.425in" height="4.977777777777778in"}

Figure 3. Typical Internally Lighted Wind Cone.