विंडसॉक (None: Windsock)

What Is a Windsock?

A windsock is a truncated fabric cone — typically orange — suspended from a pole near the threshold of a runway. It is one of the oldest and simplest aviation weather instruments still in active use. The windsock provides pilots with an immediate, intuitive visual indication of wind direction and approximate wind speed at a specific point on the airfield, without requiring any electronic equipment to read. Every certified aerodrome worldwide is required to display at least one windsock.

How It Works

Wind enters the wide open mouth of the cone and exits through the narrow tail. The cone aligns itself downwind, so the tail points in the direction the wind is blowing toward, while the open mouth faces into the wind — the direction from which wind is coming. Wind speed can be estimated by the angle at which the sock is lifted:

• Hanging limp: Calm or less than 3 kt.
• Half extended (≈45°): Approximately 7–8 kt.
• Fully extended (horizontal): 15 kt or more.

Air Traffic Control provides pilots with precise wind readings from anemometers, but the windsock gives a rapid visual cross-check — particularly useful during a visual approach or circuit when the pilot needs to judge crosswind component without consulting instruments.

Types and Standards

• ICAO standard: Orange fabric, 3.6 m long with a 0.9 m diameter open end; visible from at least 300 m.
• Illuminated windsocks: Internally lit for night operations — a mandatory requirement at aerodromes with night flying.
• Multiple socks: Large airports place windsocks at each runway end and at mid-field to detect wind shear or localised variation.
• Helipad socks: Smaller versions are used on hospital and offshore platform helipads.

Interesting Facts

• The windsock was first standardised for aviation use in the early 1920s — predating electronic weather instruments at airfields by decades.
• At Lukla Airport in Nepal (VNLK), one of the world's most dangerous airstrips, the windsock is particularly critical because the runway ends at a cliff; pilots must commit to the approach wind conditions before they can safely abort.
• Windsock orange is a globally standardised colour chosen for high visibility against green terrain and grey tarmac — the same rationale used for aviation life rafts and distress flares.
• Some airports paint a stylised windsock on helicopter landing pads and grass strips where a physical sock cannot be permanently installed.