Considering the Difference Between EASA Minor & Major Changes – Sofema Aviation Services (SAS) www.sassofia.com reviews potential changes to Type Certificates (TC) and Supplemental Type Certificates (STC).
Introduction
When changes are needed to an airframe or onboard equipment, there are two options:
- To initiate a modification by the type design holder (manufacturer),
- To request a third-party Supplemental Type Certificate (STC).
Note: The choice is determined by considering whether or not the change constitutes a new design (i.e. introduces risk not considered in the first type design).
If Yes – The Design Approval Holder (DAH) must develop and approve a modification to the type design.
If No (The regulatory authority agrees the change does not introduce new risk).
- The Supplemental Type Certificate (STC) option is available.
o An STC is less expensive because the design change can be developed by a specialized design organisation.
o STC’s provide a generally more flexible and efficient process than going through the original manufacturer.
o The STC defines the product design change, states how the modification affects the existing type design, and lists serial numbers of the aircraft affected. It also identifies the certification basis for regulatory compliance for the design change.
Note: The STC Holder is responsible for the continuing airworthiness not just of the modification but the interface as well – which means the impact on the original type design.
Changes requiring a new type certificate (21.A.19)
Any natural or legal person proposing to change a product shall apply for a new type certificate if the Agency finds that the change in design, power, thrust, or mass is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required.
Minor Changes
Have No appreciable effect on:
- A “minor change” has no appreciable effect on the mass, balance, structural strength, reliability, operational characteristics, operational suitability data, or other characteristics affecting the airworthiness of the product or its environmental characteristics.
Major Changes
Have an appreciable effect on:
- A “Major Change” has an appreciable effect on the mass, balance, structural strength, reliability, operational characteristics, operational suitability data, or other characteristics affecting the airworthiness of the product or its environmental characteristics.
Note: All deviations from a type design are considered as changes and must be approved by the authority.
Examples related to European Technical Standard Order
Any change has to be substantiated regardless if the change is classified as minor or major; the responsibility is on the ETSOA Holder.
As a general criterion, a change could be classified as “minor” if it does not require a complete re-investigation for assessing compliance to the applicable requirements.
The ETSOA holder can perform minor changes.
- Shall inform EASA about minor changes.
Note: Major changes lead to a new ETSO authorization.
For minor changes to ETSO articles, the root part of the part number is unchanged and the minor change is identified via “open brackets”. Ref 21.A.603(b)
Note: Major changes are submitted through the EASA applicant portal by creating a new application and selecting ETSOA – Initial Approval.
Next Steps
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Design Approval Holder, ETSOA, EASA changes, Design Holder, TC, Type Certificates, European Technical Standard Order, EASA Major Changes, EASA Minor Changes, EASA, DAH, SAS blogs, ETSO, EASA Supplemental Type Certificates, Regulatory and Vocational training, EASA regulatory compliant, Airworthiness, STC
