FAA L-806
An FAA L-806 is a supplemental aviation windsock required for airfields without a 24-hour air traffic control tower, whether ATCT is full or part-time.
Title 14 CFR Part 139 Airport Certification requires that an airfield must have a wind cone that provides surface wind direction information to pilots. If an L-807 primary wind cone is not visible to pilots on approach and takeoff at each runway end, airfields must employ supplemental wind cone(s).
Internally lit wind cones are required if the airfield is open for night flights. The illuminated wind cone must present a constant intensity to the pilot.
The supplemental L 806 wind cone must be located near the runway end so that pilots have an unobstructed view during either landing or takeoff operations. The preferred location is on the left side of the runway when viewed from a landing aircraft. However, it may be located on the right side of the runway where conditions such as the existence of another runway, taxiway, apron, terrain problems, or navigational aids preclude its installation on the left side.
Dimensions
Size 1 – 8′ (2.5 m) in length and 18″ (0.45 m) in throat diameter
Size 2 – 12′ (3.75 m) in length and 36″ (0.9 m) in throat diameter
Fabric
The windsock’s fabric may be cotton, a synthetic material or a blend of the two, and may be coated. The fabric must be water repellent and may be natural (white), yellow, or orange in color. No lettering or logos allowed. 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.
Structure
The 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.
References:
FAA AC 150-5390-2 – Heliport Design
FAA AC 150/5340-30 – Design and Installation Details for Airport Visual Aids
FAA AC 150/5345-27 – FAA Specification for Wind Cone Assemblies
