Obstacles (Wind Farms) outside the vicinity of a CASA certified aerodrome - draft advisory circular 139.E-05 v1.0

Closed 10 Feb 2021

Opened 13 Jan 2021

Feedback updated 1 Jun 2021

We asked

From 13 January 2021 to 10 February 2021, aerodrome and aircraft landing area operators, planning authorities, pilots, persons involved in the design, construction and operation of wind farms and wind monitoring masts and internal CASA personnel were invited to review and provide feedback on the suitability of guidance material on matters that should be considered when assessing a wind turbine development so that all necessary measures can be taken to protect aviation safety.

You said

We received a total of 6 responses, all from different areas of industry. Three respondents consented to having their comments published, 2 did not give their consent and one respondent was a CASA officer.

Summary of feedback

Most respondents recommended changes that were editorial in nature.

Several matters were raised that required further consideration and clarification, including:

  • Aeronautical studies commissioned by wind farm proponents can lack independence and down-play the extent and impact of the wind farm proposal on aviation activities. There is potential need for an independent accredited auditor to review aeronautical assessments to ensure non-biased assessments are being provided to CASA.
  • Inclusion of more detail in the 'early review by proponent' stage to ensure proponents do not miss uncertified aerodromes and aircraft landing areas nearby to proposed sites.
  • Providing clear guidance on what conditions and criteria CASA will base advice upon when aviation hazard lighting is recommended.

The need for the Department of Infrastructure, Transport, Regional Development and Communications to update the National Airports Safeguarding Framework Guideline D: Managing Wind Turbine Risk to Aircraft to reflect current windfarm technology was noted.

We did

Next steps

All comments provided by industry have been carefully considered and where appropriate, incorporated into the AC. The AC 139.E-05 v1.0 - Obstacles (wind farms) outside the vicinity of a CASA certified aerodrome is now available on the advisory circular page of the CASA website.

Published responses

View submitted responses where consent has been given to publish the response.


This is the second version of an advisory Circular (AC) which relates to obstacles (wind farms) outside the vicinity of a Civil Aviation Safety Authority (CASA) Part 139 of the Civil Aviation Safety Regulations aerodrome. AC 139.E-05 v1.0, replaces AC 139-18 v0 - obstacle marking and lighting of wind farms, which was withdrawn from circulation in 2009.

The purpose of AC 139.E-05 v1.0, is to provide guidance and advice about the CASA assessment of wind farm related aviation hazards in relation to:

  • obstacles outside the vicinity of a Part 139 Aerodrome
  • wind farm hazard lighting
  • CASA’s assessment of windfarm related aviation hazards or obstacles.

This guidance would be of use to:

  • persons involved in the design, construction and operation of wind farms and wind monitoring masts
  • proponents of wind farms and wind monitoring masts
  • planning authorities
  • aerodrome and aircraft landing area operators
  • the Civil Aviation Safety Authority.

The revision of this AC is not a result of the newly made Part 139 which came into effect in August 2020.

Why your views matter

We are seeking feedback on whether the AC provides adequate guidance on the CASA’s assessment of wind farm related aviation hazards and obstacles, and if is fit for purpose.

A copy of the draft AC is provided below and within the consultation. Please read the AC before providing your feedback in the online survey.

What happens next

At the end of the response period for public comment, we will review each comment and submission received through the online response form. We will make all submissions publicly available on the CASA website, unless you request your submission remain confidential. We will also publish a Summary of Consultation which summarises the feedback received, outlines any intended changes and details our plans for the AC.

To be notified of any future consultations, you can subscribe to our consultation and rulemaking mailing list


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