Aviation Grade Wind Direction Indicators
The legislation pertaining to Windsock Assemblies, also known as Wind Direction Indicators (WDI) or Illuminated Wind Direction Indicators (IWDI), is quite complex. While we have provided a brief overview here, it is important to refer to CASA for the most accurate information.
Wind significantly affects aircraft performance, especially for smaller planes. Windsocks are critical because they:
- Guide runway selection for take-off and landing
- Provide a Wind Speed Indicator which helps pilots assess headwinds, tailwinds, and crosswinds
- Indicate potential wind shear and turbulence
- Assist in calculating take-off and landing distances
- Provide immediate visual reference for quick decision-making
For safety and efficiency, pilots rely on windsocks to make informed choices during critical flight phases.
At Windsocks Australia, we provide CASA compliant Wind Direction Indicators to ensure your airfield meets safety standards and supports safe aircraft operations.

Extracted from CASA Advisory Circular - AC 91-02 v1.2. Regulation 91.380 requires the pilot to land and take off into wind to the extent practicable unless the AFM/POH allows the aircraft to land or take off downwind or crosswind, and the pilot is satisfied that traffic conditions at the aerodrome enable such a landing or take-off to be carried out safely.

Controlled and Un-Controlled Aerodromes - Illuminated (IWDI) and Non-Illuminated (WDI) Wind Direction Indicators
CASA Manual of Standards MOS 139 Chapter 8 for Aerodromes and Chapter 9 for illuminated Aerodromes sets out the requirements for a WDI and IWDI.
Our CASA compliant IWDIs:
- are designed to comply with MOS 139 for both Non-Illuminated and Illuminated WDIs
- accomodate the CASA Standard Size: 3650mm x 900mm x 225mm (length, mouth Ø, tail Ø) Windsock
- have a full Stainless Steel Dual Frame design with Stainless Steel Sealed Bearings - making them very robust and 'fit for purpose' for Australian conditions
- are illuminated with a CASA compliant dual obstruction beacon and 4 high intensity LEDs (again designed around CASA MOS 139, 9.38)
- are mounted to a 6m Extra Heavy Duty Mid Hinged Counter Weighted Galvanised Pole - which is able to be readily lowered and prevents working at height issues
- are made in Australia and fit for Australian conditions
- are able to be retro-fitted to existing installations - depending on the nature and condition of the existing installation
For Non-Illuminated Wind Director Indicators (WDI), the top section is modified to remove the Cross Arms and therefore illumination.
As we use an Extra Heavy Duty Mid Hinged Pole, we are able to engineer pole footing designs for all Wind Regions in Australia, including and up to Wind Region D (Cyclonic).
Please Contact Us for further information.

Engineered to comply with the requirements of MOS 139 (9.38) - LED lights illuminate the Windsock, ensuring at least 100 lux of bright, consistent light across the entire Windsock length and around its full 360-degree circumference.
Night Operations
Where an aerodrome is intended for night use, at least one Illuminated WDI (IWDI) is required.
Windsocks Australia IWDI's have been engineered to comply with the requirements of MOS 139 (9.38) through the use of new generation LED Flood Lights and an Obstruction Beacon.
"New generation" IWDI
Windsocks Australia provides a "new generation" solution to IWDI's, comprising:
- full stainless steel 304 Frame and Cross Arm structure
- 2 sets Sealed Bearings 316 Stainless Steel
- pre-wired for easy installation on site and an Electrical Compliance Certificate to Australian Standards issued by a Licenced Electrical Contractor
- the whole 'rounded' adaptor design - together with the pole - also significantly reduces the chance that the Windsock will catch, and rip.
Compared to other legacy solutions, ours was designed to be easier to install, significantly less weight (approximately 50% less), utilise the latest innovations in LED illumination technology and with its full Stainless Steel Construction provide years of trouble free operation.
Windsocks Australia warrants the IWDI solution at 5 years with a significantly longer life with regular inspection.


Helicopter Elevated HLS - Illuminated Wind Direction Indicators (IWDI)
Windsocks Australia also manufactures CASA compliant elevated HLS Windsock assemblies (IWDIs) for Hospital Emergency and other elevated Helipads.
- they are designed to comply with the relevant CASA Guidelines for elevated HLS assemblies which allow for a smaller format Windsock frame, down to 1200mm in length and 300mm Ø mouth diameter - refer CASA AC 139.R-01 V1
For more information on our HLS IWDIs refer here.
CASA Standard Aviation Windsocks



