Review of legacy airworthiness directives unique to Australia

As part of our review of legacy Australian airworthiness directives (ADs) for general aviation (GA) aircraft, we asked for feedback on:

• the potential repeal of 18 structural fatigue ADs that impose unique Australian requirements affecting GA aeroplanes under 5,700 kg
• the policy framework used to assess whether these ADs remain appropriate, justified and proportionate
• the proposal for CASA to issue a direction that aims to clarify and expand the existing continuing airworthiness responsibilities for ageing aircraft used in air transport operations.

About this consultation

This consultation was open for a 4-week period from 16 April 2026 to 14 May 2026.

The 18 structural fatigue ADs proposed for repeal make up the first category of ADs assessed under the policy framework. We sought feedback on the policy proposal and the framework from aircraft owners, operators, and maintainers, as well as industry representative groups and other stakeholders to help inform a balanced and proportionate outcome.

We will undertake separate consultations on other categories of unique Australian ADs assessed in future as part of the review.

We received a total of 46 responses through the Consultation Hub and via direct email. Respondents identified as one or more of the following: pilot, aircraft owner, aircraft operator, aircraft maintenance engineer/LAME, aircraft maintenance organisation, industry representative organisation, aeronautical engineer, design engineer, CASA officer.

Of the respondents who made written submissions, 36 consented to publication of their submission and 10 requested that their submission remain confidential.

Summary of feedback

The following is a summary of the key issues raised by respondents organised into broad themes. Although this summary does not attempt to describe every issue raised in the feedback, all consultation feedback has been examined and considered in detail.

The summary also does not represent our view or an agreed policy position. Rather, it reflects the different viewpoints of stakeholders received through consultation.

Policy framework and approach

In relation to the policy framework to guide the review of categories of ADs and our overall assessment approach, most respondents supported the framework and approach, noting they are well-founded, appropriate and sensible. Respondents were also supportive of taking a more risk-based and flexible approach to aircraft safety.

The importance of alignment with contemporary airworthiness philosophy and adopting a consistent approach across the ageing aircraft fleet in relation to managing continued airworthiness was also noted by respondents. Some suggested extending the framework to assess other unique Australian ADs, which aligns with our intention that further categories of ADs will be assessed in future as part of the review. A small number of respondents indicated that the framework is lengthy or complex.

Among the responses, there were 2 alternative policy approaches put forward. One of these raised whether the threshold policy question should be whether the life limit in the Australian unique AD would have been an Airworthiness Limitation had the aircraft type certification been under the Federal Aviation Administration (FAA) Regulations 14 CFR Part 23 Amendment 23-26, which also introduced Instructions for Continued Airworthiness (ICA) as a mandatory requirement. Another response questioned whether 50-year-old aircraft are viable at all. While out of scope, this response suggested that allowing experimental aircraft to be used in CASR Part 137 and Part 138 (aerial work) operations would provide valuable data about the safety and viability of these aircraft, which could be used for certification in future and enable retirement of the current ageing aircraft fleet.

Consistency with international standards and alignment with State of Design ADs and OEM requirements

Most respondents favoured alignment with State of Design (SoD) requirements and manufacturer ICAs, with additional comments generally reflecting that this provides the most effective, up-to-date, evidence-based and authoritative method for managing continued airworthiness. Some respondents indicated that additional published guidance would help ensure that any non-mandatory manufacturer service bulletins are appropriately considered and actioned. 

In relation to Australia’s current policy settings in CASR Part 39 to accept SoD ADs and to only issue an Australian AD where local circumstances require that action, one respondent noted concern that Australia’s unique structural fatigue ADs are not based on a known defect in the Australian fleet. Rather, they are based on now repealed unique design standards that required our (or our predecessors) engineering staff to provide fatigue lives for Part 23 type aeroplanes. This response also noted that the UK Civil Aviation Authority cancelled several fatigue related ADs for non-UK built aircraft in 2007 at the time the European Union Aviation Safety Agency (EASA) took responsibility for airworthiness of these aircraft types, and that EASA has not reissued these ADs. Another respondent noted that there is a risk over time of corporate memory loss at CASA, meaning that the reasons for issuing ADs for certain aircraft models and not others can get lost in history.

Other suggested alternatives to mandating fixed retirement lives in unique Australian ADs included targeted inspection and on-condition maintenance approaches using modern non-destructive testing techniques and supported by current global data. One respondent suggested that a once-off inspection of higher-risk areas should be undertaken at the high time/cycle limit, with the results to be shared with the SoD/OEM to support continued product confidence. Another respondent also suggested modifying the fixed retirement life to an inspection and reporting requirement.

Several respondents indicated that some ADs could be repealed, with others being retained. Those who provided additional comments on this suggested it may be appropriate to retain ADs that mandate manufacturer structural inspection programs supported by the SoD, which would be a mechanism to ensure compliance. Some respondents suggested that additional factors should be considered such as aircraft storage, usage, environmental conditions and operations. However, most respondents did not provide additional context for which ADs should be retained and their reasons for this.

Safety considerations

Through the consultation, we sought to understand whether industry stakeholders or aircraft owners/operators were aware of specific accidents, incidents or defect data that would suggest the identified ADs are required to address an unsafe condition. The overwhelming majority of respondents indicated that they were not aware of any such data or were unsure.

One respondent indicated an alternative view that accident, incident and defect data is the reason that all international airworthiness standards have for decades required Airworthiness Limitations to manage structural fatigue proactively, rather than reactively.

In relation to the expected safety impact of removing the identified Australian unique structural fatigue ADs, some respondents suggested caution citing the historical reasons why Australian structural fatigue ADs were issued and noting that the old FAA CAR 3 standard that many aircraft were certified under did not require fatigue lives to be taken into consideration. In contrast, this was made mandatory for aircraft certified under FAR Part 23. 

Respondents aligned with these views also noted that the Australian ADs were issued for a valid reason with a solid engineering basis and that fatigue cracking will occur in ageing aircraft not as a matter of ‘if’, but more a calculation of ‘when’. Concern was also noted about moving away from the additional design standard that was originally agreed upon when the aircraft was accepted into Australia. One respondent noted that the fact that other countries do not mandate fatigue lives does not make the Australian fatigue lives wrong. Others noted that the ultimate risk of removing these ADs is a catastrophic in-flight structural failure resulting in loss of life.

Many respondents who identified as pilots and aircraft owners or operators, and some maintenance engineers/LAMEs, put forward an alternate view that removal of the ADs would not give rise to safety concerns, and may provide a safety benefit. This is based on the view that increased inspection frequency and invasive or difficult maintenance tasks increases the risk of introducing maintenance-induced errors or damage and diverts maintenance resources from higher priority safety-critical tasks.

Some respondents qualified their view of no adverse impact on safety by adding the proviso that the aircraft needs to be properly maintained, including carrying out relevant service bulletins and service letters, and that the SoD/manufacturer is relied upon to act where needed.

A small number of respondents noted that aircraft covered by the ADs continue to operate overseas in harsh environmental/climate conditions and with higher airframe hours than the Australian fleet. This contrasts with the alternate view of a small number of respondents that described Australia as ‘fleet leader’ with higher aircraft flight times and cycles.

Impact on operations

Aircraft owners, operators and maintainers provided largely consistent feedback regarding the impact of the ADs on operations and on maintenance-related risks. On operational impacts, respondents noted key concerns related to the premature retirement of airframes based on hours rather than on condition, challenges in the Australian market with sourcing parts and a lack of viable replacement aircraft, lengthy grounding of otherwise serviceable aircraft, reduced availability of maintenance resources, reduced aircraft utilisation to manage hours, and the disproportionate impact of fixed-hour limits for low-utilisation operators. Across all these issues, the burden and costs on owners, operators and maintenance providers were also noted of concern.

Many of these respondents also raised maintenance-risks associated with compliance with Australian unique ADs, including potential damage to fastener holes and surrounding structures, introduced corrosion and fatigue risk due to the repeated opening and closing of sealed areas, the necessity of modifications to improve access to inspection areas, and human error in reassembly including incorrect torquing, missed defects or incorrect assembly.

A small number of respondents indicated less concern about the impact of ADs, including one response that noted that the AD requirements are longstanding and a known factor of a planned maintenance program.

Proposed direction in relation to aircraft used in air transport operations

A small number of respondents commented on our proposal to issue a direction requiring that ageing aircraft considerations be addressed in the continuing airworthiness management of aircraft used in air transport operations. Respondents largely agreed that the proposal is appropriate, proportionate and reflects the required level of safety for carrying passengers.

Respondents also agreed that additional requirements should be targeted, evidence-based and aligned with manufacturer’s ICA and SoD ADs. Some respondents specifically indicated support for a maintenance program under CASR Part 42, with one stating the view that Schedule 5 is not sufficient to maintain their aircraft to conduct air transport operations. One respondent commented on other usage profiles, noting that joy flight aircraft and high G-stressed aerobatic flying aircraft should have higher requirements than 'normal' flying aircraft.

Overall, the responses on this topic indicate broad support for a proposed direction in relation to ageing aircraft continuing airworthiness management.

Other comments

A small number of respondents provided comments and feedback in addition to the above themes, some of which cover issues that are beyond the scope of this consultation. These comments are noted and any out-of-scope feedback will be considered outside of the AD review. Some comments relate to Australian ADs covering other aircraft, which will be considered as part of the review as appropriate.

Two respondents provided additional historical context for the issue of Australian unique structural fatigue ADs and the regulatory framework and policy that applied prior to 2009. These responses also included references to various National Aviation Authority resources and to research papers on structural fatigue. These insights are noted and appreciated.

One response raised a range of issues and concerns affecting GA more broadly, suggesting that a holistic approach should be taken to preserve aviation safety. These comments are also noted, appreciated and will be examined outside of the AD review.

We thank all respondents for their constructive input. The consultation has provided valuable insights and has highlighted important issues that will be carefully considered in progressing the potential repeal of unique Australian structural fatigue ADs.

The consultation has also highlighted the cost burden and other impacts that these ADs are having on industry and the challenges faced by Australian operators and maintainers arising from limited supply of parts and the lack of options to update aircraft fleets. We will consider this as part of our ongoing analysis.

We will continue with work on the proposal to repeal the 18 identified structural fatigue ADs and on developing an appropriate direction for the continued airworthiness management of aircraft used for air transport operations. We will also consider information and guidance that may assist aircraft owners and operators more broadly to manage the continued airworthiness of their ageing aircraft.

In addition to this, we will continue with the review of other categories of unique Australian ADs. This includes Beechcraft wing bolt ADs and other structural fatigue ADs affecting GA aircraft under 5,700 kg not included in the current proposal.

Separate consultations will be undertaken on each AD category being considered for repeal and stakeholders interested and experienced in these AD categories are encouraged to provide further feedback.