Changes of type design are classified as follows:
1) A "minor change" is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, noise, fuel venting, and emissions, or other characteristics affecting the airworthiness of the product.
2) All other changes are "major changes".

Minor changes in a type design can be undertaken only after the holder of the type certificate has received CAA approval for minor design change. When such design change has been completed, the holder of the type certificate should provide CAA with all the related substantiating and technical data. In addition, the holder of type certificate shall return the original type certificate to the CAA and apply for revising type certificate, if deemed necessary.

In the case of a major change in type design, the applicant must submit substantiating data and necessary descriptive data, along with a statement that the changed type design complies with the requirement stipulated in Article 23 of the regulations herein. The major change of type design can only be undertaken after CAA approval. In addition, the holder of type certificate shall return the original type certificate to CAA and apply for revising type certificate, if deemed necessary.

When the issuance of an Airworthiness Directive for a type certified aircraft product is deemed necessary by CAA, the holder of the type certificate must submit appropriate design changes to CAA for approval. When approved, the holder shall make information on the design changes available to all operators of same type of product.
When a design change to the type design of type certified aviation product is deemed advantageous to enhance the flight safety of that product, as determined by CAA or by the holder of the type certificate, the holder of the type certificate may submit appropriate design changes to CAA for approval. Upon approval, the holder shall make information on the design changes available to all operators of same type of product.

An applicant for changes to type design, operation limitations, Type Certificate Data Sheets (TCDS) and restrictions relating to the type certified aircraft product, must show that the changed product complies with the airworthiness requirements applicable to the category of the product in effect on the date of the application for the change and/or any other applicable noise, fuel venting and exhaust emission requirements.
Except as provided in the first paragraph of this Article, if an applicant shows that the amendment of a regulation and/or that a CAA previously granted equivalence of safety, as in effect on the date of application of original type certificate, brings no significant impact on flight safety, the previously defined requirement may be kept in effect, if approved by CAA, for the changed product.