Overview

We are seeking feedback on proposed amendments to the Part 121 Manual of Standards (MOS). The changes replace expiring provisions, amend alternate aerodrome planning requirements and TAWS definitions in the rules.

Who is affected

The proposal is relevant to Part 121, Part 135, Subpart 121.Z and CASA EX74/24 operators as follows:

• Part 121 operators should review all the policy topic questions
• Part 135, Subpart 121.Z and operators of 10-13 seat aeroplanes under exemption CASA EX74/24 should review changes 2, 3 and 8.

Proposed changes

The proposed changes include:

1. Maintaining a consistent approach to aviation rescue and firefighting services (ARFFS) at Australian aerodromes - the requirement for ARFFS to be planned at extended diversion time operations (EDTO) en-route alternate aerodromes will not be introduced.
2. Replacing transitional RNP-based engine-out departure procedure (EODP) obstacle assessment area (OAA) requirements for operators with highly capable aeroplanes.
3. Permitting reduced pre-flight destination aerodrome wet or contaminated pre-flight landing performance where an alternate aerodrome is planned.
4. Limiting alternate aerodrome minima to be no higher than destination aerodrome minima.
5. Improving alternate aerodrome minima requirements by adding an extra item to the alternate aerodrome minima table.
6. Allowing isolated destination aerodromes to be planned to have a destination alternate aerodrome.
7. Aligning instrument approach classifications to reflect updated Part 91 MOS changes.
8. Amending the definition of TAWS Class-A and TAWS Class-B to permit an earlier version of the technical specification.

For more detail on these changes please read the attached Summary of proposed change.

Legislation

Part 121 of the Civil Aviation Safety Regulations (CASR) 1998 came into effect in December 2021. Some of its new or updated requirements replaced those in the earlier Civil Aviation Regulations 1988 and Civil Aviation Orders. However, certain provisions had delayed start dates. These delayed start dates provided operators with more time to transition to the new requirements. In addition, some earlier requirements were kept in place for specific matters until CASA and industry could establish future policy and legislation.

Previous consultations

Prior to the release of this consultation, CASA consulted internally as well as externally via the Aviation Safety Advisory Panel (ASAP) and the Part 121 Technical Working Group (TWG), consisting of representatives from CASA and the larger aeroplane air transport sector.

The proposed amendments are also partly in response to industry feedback received by CASA since the commencement of the flight operations regulations in December 2021.

Why your views matter

Your feedback will help us make sure the proposed requirements are suitable, the final legislation is clear, and it 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 regulatoryconsultation@casa.gov.au 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 2522OS, which provides background on the proposed MOS amendments
• Consultation draft - Part 121 (Australian Air Transport Operations—Larger Aeroplanes) Amendment Manual of Standards 2025
• 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 proposed legislation will be considered. Relevant feedback that improves upon the proposed instrument will be incorporated into the final instrument.

Post-implementation review

CASA will monitor and review the proposed amendments affecting the Part 121 sector, and for the TAWS changes, the Part 135 sector. We will also continue work on proposed further changes, to better support aeroplane air transport operations.