Fabricate versus Manufacture : an important distinction in aviation
In the aviation industry, particularly under the framework of Part-21 design and production, terms like “fabricate” and “manufacture” are often used interchangeably. However, these terms hold distinct meanings that are critical for professionals to understand. This article explores the nuances between these two processes, highlighting their unique characteristics, regulatory requirements, and practical applications.
Fabrication
Fabrication refers to the process of creating while performing maintenance and/or an alteration. Critically, parts fabrication must be performed within the privileges and limitations of the certificate holder’s authorisation and ratings, and in accordance with his/her established quality control system.
Key characteristics of fabrication include:
- Purpose: Parts are created for specific maintenance or modification activities
- Certification Context: Items fabricated must comply with applicable design data approved by the Type Certificate Holder or under a DOA approval. There is no accompanying Form 1 for the part.
- Commercial Intent: Fabricated components are not sold as standalone products or for mass production; they are integrated into larger assemblies or systems as part of maintenance activity.
The UK CAA has issued extra guidance on the fabrication of parts under 145 in the CAP 2999 document. There are some very specific guidelines in this document on what is and is not allowed under 145 fabrication – these are common to FAA and EASA. For example:

Manufacture
Manufacture refers to the process of producing components or parts under Part-21 Subpart G and Subpart F (POA) for mass production of parts. This activity involves production and delivery of parts intended for distribution, often for integration into various aircraft or systems.
Key characteristics of manufacture include:
- Purpose: Manufactured parts are new components designed for distribution or installation, often as part of a Supplemental Type Certificate (STC) or Minor Modification.
- Certification Context: These parts must adhere to approved design data and rigorous production quality controls under Subpart G. A Form 1 is issued with each part.
- Commercial Intent: Manufactured components are produced for sale or widespread aviation use, including one-off changes or modifications.
Part marking
An organisation approved under Part 145 is permitted to fabricate parts solely for its own use, in compliance with approved design data (145.A.42(cb)(iii)). The part number is specified in the design data. Additionally, the organisations identity and identification codes such as year of fabrication should be marked on the part for traceability purposes.
Example : EASA.145.XXXX 2025JAN
For parts based on Supplemental Type Certificate (STC) or minor modification data, additional identifiers such as “EPA” or “UKPA” must be appended to distinguish them from Type Certificate Holder (TCH) parts. Whether EPA or UKPA is used depends on whether it’s a UK CAA Part-21.J or EASA Part-21.J DOA.
Example : 21U307PD0113 UKPA

Practical example
Following our previous article on external livery changes, consider the replacement of external technical markings. In such cases, design data may not be readily available from the Type Certificate Holder. Here’s how fabrication and manufacture apply:
- Fabrication scenario: A Part 145 organisation may fabricate a kit for a repainting project if the capability is outlined in its MOE and supported by DOA-approved design data.
- Manufacture scenario: A Part-21G organisation may manufacture and supply the kit, ensuring compliance with approved design data supplied by the Type Certificate Holder or a DOA.
Conclusion
Understanding the distinction between fabrication and manufacture is essential for ensuring compliance and efficiency in aviation design and production. Fabrication serves targeted maintenance needs, while manufacture addresses broader, commercial production requirements.
With an integrated DOA and POA, we can help you with all of your design and production needs. If you’re a DOA and you need a POA to manufacture your parts, we’re here to help. Get in touch via info@knsi.co.uk .