Plume rise assessments - Draft Advisory Circular 139.E-02 v1.0

Closed 20 May 2022

Opened 5 May 2022

Feedback updated 8 Mar 2023

We asked

About this consultation
We sought industry feedback between 5 and 20 May 2022 on Plume rise assessment - draft Advisory Circular 139.E-02 v1.0. The consultation proposed amendments to the current Advisory Circular (AC). The key amendment proposed was the incorporation of the MITRE Exhaust Plume Analyzer as a tool to determine the probability of an aircraft experiencing turbulence near a plume rise.

It was also proposed that the AC was amended to clarify CASA's role in the assessment process and that Land Use Planning Authorities (LUPAs) are the decision maker on applications from proponents that include a plume rise.

Stakeholders were asked whether the proposed changes provide adequate guidance on how to obtain advice from CASA and CASA's process for assessing plume rises.

Most responses received were from aircraft operators, with 3 respondents identifying as consultants on plume rise assessments and 2 as representing airport operators.

You said

Summary of feedback
We received 35 responses to this consultation. Thirty-four respondents supported the proposal, with 9 of these respondents recommending changes of a relatively minor nature to the proposal.

One respondent opposed the proposal and cited a 2006 US FAA paper. However, in 2015, after further study, the US FAA concluded that plumes in the vicinity of airports could create hazards to aircraft in critical flight phases that would be incompatible with airport operations. The proposed AC is based on the 2015 US FAA position.

The common issues, questions or suggestions were around the ability of CASA to:

  • influence the decision of Land Use Planning Authorities (LUPAs) who are decision makers on proposals for facilities which emit plumes
  • provide timely assessments, and
  • assessment of impacts of light turbulence.

Overall, the majority of respondents supported the proposal.

The principal change is the adoption of the MITRE EPA as the tool that will support the delivery of an aircraft-type specific assessment of the probability of encountering turbulence near a plume rise. Some comments were based on an assumption that CASA has a decision-making role in relation to proposals involving a plume rise. The draft AC was therefore amended to clarify that the role of CASA in the assessment process does not extend to decision making on applications as this is the role for the relevant LUPA.

We did

We have amended the AC to reflect comments provided by respondents and published AC 139.E-02v1.0.

Published responses

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


The purpose of this advisory circular (AC) is to:

  • provide a standard method of determining the probability of an aircraft experiencing turbulence when flying in the vicinity of a facility emitting a vertical exhaust plume
  • ensure that the impact of plumes can be assessed in a consistent and reliable way
  • provide guidance to stakeholders involved in the approval, design and operation of facilities with vertical exhaust plumes to assess the potential hazard from a plume to aircraft operations
  • provide guidance to stakeholders on the plume rise assessment process.

AC 139.E-02 v1.0 incorporates the use of the Exhaust Plume Analyzer (EPA) tool developed by the MITRE Corporation for the United States’ Federal Aviation Administration (US FAA) and explains how the EPA tool has been adapted for consistency with Australian legislation.

This AC will be of interest to:

  • land use planning authorities including local councils, State/Territory planning agencies and the Department of Infrastructure, Transport, Regional Development and Communications
  • aerodrome operators
  • aircraft operators
  • proponents of facilities that emit plumes such as power stations and road tunnels.

Why your views matter

CASA recognises the valuable contribution that community and industry consultation makes to the regulatory development process. For this reason, we are seeking feedback on whether the draft AC provides adequate guidance on: 

  • the process to obtain advice from CASA on the potential for a plume rise proposal to create risk to the safety of aircraft operations
  • the process CASA follows to assess plume rises.

This is the third revision of the AC relating to the conduct of plume rise assessments and replaces AC 139-05 v3.0 – Plume rise assessments issued in January 2019.

Documents for review

All documents related to this consultation are in the ‘related’ section at the bottom of the page. A copy of the draft AC is provided below as well as appearing on the designated page of the survey.  There is also an MS Word copy of the online survey to make it easy for you to peruse or coordinate feedback within your organisation.

Please submit your feedback through the Consultation Hub using the survey provided. If you are unable to provide feedback this way, please contact us for advice through

What happens next

At the end of the response period for public comment, we will review each comment and submission received. We will make all submissions publicly available on our 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.


  • Aerodrome operator


  • Airworthiness / maintenance