Proposed amendment to Part 121 MOS to replace expiring provisions and make minor changes - some relevant to Part 135 - (CD 2522OS)

Closes 10 Nov 2025

Change 8 - Amend definition of TAWS Class-A and TAWS Class-B (relevant to Part 121, 135, 121.Z and CASA EX74/24 operations)

Policy Aim

Allow aeroplanes required to be fitted with Terrain Awareness and Warning System (TAWS) Class-A and TAWS-Class B that are (E)TSO-C151a, as well as the (E)TSO-C151b and subsequent versions.

Proposed Policy

We propose to amend the definitions of TAWS Class-A and TAWS-Class B in section 11.24 of the Part 121 Manual of Standards to refer to (E)TSO-C151a and subsequent versions in place of (E)TSO-C151b and subsequent versions.

As the CASR Dictionary relies on these definitions for use across the CAR and CASR, the proposed change will affect every occurrence of the defined terms ‘TAWS Class-A’ and ‘TAWS Class-B’ within these sets of regulations and their subordinate instruments (such as Civil Aviation Orders, Manuals of Standards, exemptions, directions, approvals, authorisations, permissions, etc).

Relevant to the flight operations regulations, the terms TAWS Class-A and TAWS Class-B, in addition to the Part 121 MOS, are also used in the Part 135 MOS, the 10-13 seat aeroplane exemption CASA EX74/24 and the Subpart 121.Z TAWS regulations.

Question 1: Do you agree with policy aim of permitting TAWS Class-A and TAWS-Class B that are (E)TSO-C151a and subsequent versions?
Question 2: Do you agree that the proposed policy achieves its intended aim?