Wind Cone

A Wind Cone (also known as a windsock or wind tee) is a fabric cone suspended from a mast that visually indicates wind direction and approximate wind speed. It is one of the most basic and universally recognized visual aids at airfields. The cone is mounted on a swivel so it can rotate freely to align with the wind. The angle of the cone relative to the horizontal mast indicates wind speed: fully extended (horizontal) indicates strong winds (≥15 knots), while drooping indicates lighter winds. The colour is typically orange and white bands, or solid orange, for high visibility. For night operations, the wind cone may be internally illuminated (with a light source inside the mast) or externally illuminated (with floodlights).

The wind cone's purpose is to give a pilot instant, no-equipment-required wind information they can read visually during approach, taxi, or takeoff — both its direction, from which way it points, and its rough strength, from how far it extends. This matters because wind is one of the first things a pilot needs to judge before committing to a particular runway or approach path, and a glance at the windsock provides that answer faster than waiting for a radio call or checking an instrument.

Its high-visibility orange banding and simple, universally recognised shape also mean it functions the same way at virtually every airfield in the world, giving pilots a consistent visual reference they can trust regardless of location — a role that becomes even more important as a backup when other wind-reporting systems are unavailable or under question.

Installed at all airfields, heliports, and military landing zones where wind information is critical. Typically placed near the runway threshold or at a central location on the airfield, visible from both the approach and the apron. Used by pilots during takeoff, landing, and ground operations to assess wind conditions. Also used at fire stations, emergency helipads, and offshore platforms. Wind cones are often supplemented by electronic wind sensors for more precise data, but remain a reliable backup visual indicator.

The sock is fitted to the free-rotating head of its mast so it swings to align with the wind, sited where it is visible from both the runway approach and the apron, typically near the threshold or at a central airfield location, and clear of buildings, trees, or other obstructions that could create localised turbulence and give a false reading. Mounting height and position keep the cone within the obstacle-limitation surface for the runway, and the mast's frangible coupling, where fitted, sits at the base so the assembly breaks away safely if struck. Fabric is replaced on a routine schedule directly at the mast head, without needing to relocate the mast itself.

The wind cone is suspended from a freely rotating ring or bearing at the top of a mast. The larger open end faces into the wind, and the cone fills with air, aligning with the wind direction. The angle of the cone relative to the horizontal indicates wind speed: a fully extended cone (horizontal) corresponds to winds of 15 knots or more; a 30° droop indicates about 10 knots; a 60° droop indicates about 5 knots; and a completely limp cone indicates calm conditions. The mast is often illuminated from within (using a lamp inside the mast that shines up into the cone) or from external floodlights to ensure visibility at night. The cone material is typically UV‑resistant, flame‑retardant polyester or nylon, with reinforced seams for durability.

The wind cone sits outside any electronic control loop for its primary indication function — there is no sensor, transmitter, or processor between the wind and the pilot's eye. Air pressure on the fabric is a direct mechanical input, and the resulting orientation and droop angle is the output, read visually with nothing in between. The only active system associated with the cone is its illumination, where fitted: an internal lamp or external floodlight is wired into the standard airfield lighting circuit and switched by the ALCMS or a photocell on a dusk-to-dawn basis, typically as a simple on/off circuit rather than the intensity-stepped CCR loop used for runway edge lights. A lost lamp is therefore a lighting-circuit fault, not a fault in the cone's wind-reading function, which keeps working by daylight regardless.

A wind cone assembly consists of a fabric cone, a rigid throat ring that holds the mouth open, and a swivel bearing connecting the cone to the mast so it can rotate freely into the wind. The cone fabric is a UV-stabilised, flame-retardant polyester or nylon, cut and sewn so its taper produces a consistent droop angle proportional to wind speed, with reinforced stitching at the throat and tail to resist the repeated flexing and wind loading the fabric experiences over its service life. The throat ring, typically stainless steel or fibreglass-reinforced plastic, is sewn into or clamped onto the cone's leading edge and attaches to the mast's swivel bearing via a yoke or bracket, allowing 360° rotation with minimal friction. The mast supporting the assembly is a corrosion-resistant pole — galvanized steel, powder-coated aluminium, or fibreglass — set to the standard height above ground, often designed as a frangible structure with a breakaway coupling or shear-pin base so it yields safely on impact in areas near aircraft movement. Illumination, where fitted, is provided either by an internal lamp shining through translucent fabric or by external floodlights aimed at an opaque cone.