Interim changes for specialist maintenance (D rating) approvals

We are reviewing the continuing airworthiness rules for approved maintenance organisations including Part 145 of CASR and associated legislation.

Public consultation has highlighted specialist maintenance and certification issues.

You can read the consultation summary including responses and learn about the next steps on our Consultation Hub.

These responses have informed the development of an interim measure for how we handle specialist maintenance and the D3 rating approval applications.

We will continue to work with industry to carry out the review and develop improvements.

Our approach to D3 ratings

Our preference is not to issue specialist maintenance ‘D3 other’ ratings.

Issuing a specific D3 rating would require changes to either:

  • amend the Part 145 Manual of Standards (MOS), or
  • approve a new category of specialist maintenance by issuing a legislative instrument.

These changes will not be possible while work is underway to review and improve the relevant legislation. During our review, only certain eligible specialist maintenance categories listed within the Part 145 MOS are generally considered for D rating approvals.

If you are planning to provide a service that you consider may require a D3 rating, contact us directly or talk with your airworthiness inspector to discuss.

This applies to:

  • non-approved organisations, or
  • a Part 145 Approved Maintenance Organisation planning to provide a service.

Support service providers

We recognise the important role of the various specialised support service providers to approved maintenance organisations.

Support services can still provide activities under appropriate subcontract arrangements, such as where:

  • the Part 145 Approved Maintenance Organisation (AMO) is still responsible for following their CASA-approved procedures. This includes each specialist maintenance activity. The AMO must ensure the final determination of aircraft airworthiness or aeronautical product serviceability for issuing the final Certificate Release to Service
  • the AMO has the flexibility to choose organisations with or without a D3 rating
  • subcontractors performing specialist maintenance tasks for an AMO must continue to meet the standards set out by the AMO’s CASA-approved procedures.

You can find information on specialist maintenance in the Part 145 Manual of Standards and Part 145 approved maintenance organisation requirements AMC-GM.

Last updated:
7 Mar 2022
Online version available at:
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