Proposal to amend the aeroplane TAWS rules - (CD 2311OS)

Closed 24 Oct 2023

Opened 26 Sep 2023


We want your feedback on a proposed change to the rules on the fitment of Terrain Awareness and Warning Systems (TAWS) in small turbine-engine aeroplanes.

The consultation relates to Part 121 and 135 turbine-engine aeroplanes with a maximum take-off weight of 5700kg or less and that either:

  • have a maximum operational passenger seat configuration between 10-13 seats


  • carry 10 or more persons.

Under the new Part 121 and Part 135 of the Civil Aviation Safety Regulations 1998 (CASR), the TAWS requirement for certain aeroplanes was raised from a TAWS B+ system to TAWS A.

Feedback from the aviation community advised:

  • TAWS B+ with a detailed visual terrain display would only have small (if any) safety differences compared to TAWS A for aeroplanes with a maximum take-off weight of 5700kg or less
  • the projected cost of upgrading from the old TAWS B+ to TAWS A has increased dramatically since the new Part 121 and 135 rules were made in 2018.

In response to the feedback, we set up a working group to discuss the safety differential between different TAWS standards in the context of these aeroplanes and the contemporary costs associated with TAWS A fitment.

This resulted in a recommendation that the TAWS fitment policy for certain aeroplanes be changed from TAWS A to a new version of TAWS B+.

The proposed amendment would permit these aeroplanes to be fitted with either a TAWS A or a TAWS B equipped with a visual terrain display that provides the terrain-related information outlined in section 3.5 of Appendix 1 of Technical Standard Order (TSO)-C151c for a terrain display.

We are proposing to call it TAWS-Class B+ as distinct from the previous TAWS-B+ system.

The details of the proposed changes to the legislation are provided in the attached Summary of Proposed Change.

Your feedback on these changes will help us check that the amended policy achieves an acceptable level of aviation safety for crew and passengers.

Please note that we are not proposing changes to the fitment requirement deadline of 2 December 2023.

Previous consultations

Prior to the release of this Summary of Proposed Change, a working group provided advice to CASA. Earlier consultations occurred in 2018 and between 2009 and 2012.

Why your views matter

Your feedback will help us make sure the proposed requirements are suitable, the final legislation is clear and will work as intended.

Please submit your comments using the survey link on this page.

If you are unable to provide feedback via the survey link, please email for advice.

Documents for review

All documents related to this consultation are attached in the ‘Related’ section at the bottom of the overview page. They are:

  • Summary of proposed change on CD 2311OS, which provides background on the proposed standards
  • MS Word copy of online consultation for ease of distribution and feedback within your organisation.

What happens next

At the end of the response period, we will:

  • review all comments received
  • make responses publicly available on the consultation hub (unless you request your submission remain confidential)
  • publish a Summary of Consultation which summarises the feedback received and outlines any intended changes and next steps.

All comments received on the proposal will be considered. Relevant feedback that improves upon the proposal will be incorporated into the final legislation changes.


  • Air operators
  • Pilots
  • Aircraft owner/operator
  • Passengers travelling on small commercial turbine aeroplanes


  • Air travel
  • Operational standards
  • Airworthiness/maintenance (CAR 30 and CASR Part 145 maintenance orgs)
  • Equipment standards