Part 66 and 147 changes: E propulsion requirements

Closed 28 Mar 2024

Opened 6 Feb 2024


The CAA is considering the regulatory requirements, means of compliance and guidance necessary to:

  • ensure the continuing airworthiness of electric and hybrid propulsion aircraft;
  • embrace non-conventional aircraft and aircraft with non-conventional powerplants, where some regulatory gaps have been identified;
  • support, more generally, the development of new technologies;
  • ensure smooth and flexible transitioning of AML holders in the current subcategories to obtain certification privileges for the maintenance of non-conventional aircraft; and 
  • support the competitiveness of the UK industry. One objective of the legal framework on which we are consulting is to provide a level playing field while maintaining a high uniform level of civil aviation safety in the UK.

In order to ensure that we achieve the right level of compliance and guidance we are seeking feedback on the proposals in this consultation. Your feedback will help us to better understand the potential issues or improvements that can be made to our proposals. 

Regulations (also known as Implementing Rules)

Regulations contain requirements which must be complied with. The CAA’s statutory role is to consider the required content of the regulations, consult on our proposed changes to the regulations, take consultation responses into account before forming a final view and then communicating that view to the Secretary of State (Department for Transport) in the form of an Opinion.  Our Opinions are published.  The Secretary of State makes the final decision whether to implement CAA’s proposed changes to the regulations, and the final wording of the regulations.  The proposed wording of the regulations in this consultation may well change if and when the Secretary of State decides to amend the regulations.

AMC and GM

AMC are means by which the requirements in the Implementing Rule and the Essential Requirements of the Basic Regulation to which it relates can be met. However, entities may show compliance by other means. 

An entity may choose to offer an alternative means of compliance (AltMOC) which must be reviewed and accepted by the CAA. However, it is important to note they will lose the presumption of compliance provided by the CAA AMC so it is essential for the operator to demonstrate that the AltMOC meets the intent of the Implementing Rule and the Essential Requirements of the Basic Regulation. 

GM is non-binding and provides explanatory and interpretation material on how to achieve the requirements in the law and the AMC. It contains information, including examples, to assist the applicant with the interpretation of the legislative provisions.

This consultation

This consultation document sets out our proposed changes. It includes text for specific licence sections, GM, AMC and appendices for Part 66 and relevant Part 145 content and the rationale behind each change. 

Why your views matter

It is important to the CAA that everyone has an opportunity to voice their opinion on matters that could affect them. There is also a legal requirement to consult before delivering Opinions in regulations to the Secretary of State and when adopting new or amending AMC and GM, due to the legal status of these documents.  

We welcome comments from every sector of the community. This includes the general public, government agencies and all sectors of the aviation industry, whether as an aviator, aviation consumer and/or provider of related products and services.

How to respond

The response window has been extended until 28 March 2024. We cannot take into account comments received after this date. We will assume that all responses can be published once the consultation has closed. There is an option to request for your name to remain private, but in any event your email address will never be published.

Please submit your comments below. 

What happens next

At the end of the response period, we will review and publish each comment and submission received.

Your feedback will be used to inform our Opinion to the Secretary of State on our proposed changes to the regulations and to refine the AMC and GM and guide the development of the licence and regulatory changes.


  • General Aviation
  • Regulatory bodies


  • Airworthiness
  • AMC & GM consultations
  • Licensing