Page 23 - UK Regulation Part 21 Initial Airworthiness Annex I (consolidated) March 2022

PART 21 - INITIAL AIRWORTHINESS (ANNEX I)

For major changes and those minor changes where additional work to
demonstrate compliance with the applicable typecertification basis,
operational suitability data certification basis, and environmental protection
requirements (hereinafter referred to as the ‘certification basis’) is necessary,
compliance documentation should be established in accordance with AMC
21.A.20(c).
3.3.3 Approval process
(A) For the approval of major changes, a certification programme as
defined in AMC 21.A.93(b) must be established.
(B) For major changes and those minor changes where additional work to
demonstrate compliance with the applicable certification basis is
necessary, the procedure should define a document to support the
approval process.
This document should include at least:
- identification and a brief description of the change and its
classification,
- references to the applicable certification basis,
- reference to the compliance documents,
- effects, if any, on limitations and on the approved design data,
- the name of the authorised signatory.
(C) For the other minor changes, the procedure should define a means:
- to identify the change,
- to present the change to the CAA for approval.
3.3.4 Authorised signatories
The procedure should identify the persons authorised to sign the change
before release to the CAA for approval.
3.4 Repair designs and production deviations from the approved design data
A procedure following the principles of paragraphs 3.2 and 3.3 should be established
for the classification and approval of repair designs and unintentional deviations from
the approved design data occurring in production (concessions or
nonconformances). For repair designs, the procedure should be established in
accordance with Part 21, Section A, Subpart M and the associated acceptable
means of compliance (AMC) or guidance material (GM).
4. Issue of data and information (including instructions) to owners, operators or others
required to use the data and information
4.1 General
Data and information include the operational suitability data.
4.2 Data related to changes
The data and information (including instructions) issued by the holder of a design
approval (a TC, STC, approval of a change, approval of a repair design) are intended
to provide the owners of a product with all the necessary data and information to
embody a change or a repair on the product, or to inspect it.
The data and information (including instructions) may be issued in a format of a
service bulletin as defined in ATA 100 system, or in structural repair manuals,
maintenance manuals, engine and propeller manuals, etc.
The preparation of this data involves design, production and inspection. The three
aspects should be properly addressed and a procedure should exist.
4.3 Procedure
The procedure should address the following points:
- Preparation;
- verification of technical consistency with corresponding approved
change(s), repair design(s) or approved data, including effectivity,
description, effects on airworthiness or operational suitability, especially
when limitations are changed;
- verification of the feasibility in practical applications;
- approval for the release of data and information.
The procedure should include the information (including instructions) prepared by
subcontractors or vendors, and declared applicable to its products by the holder of
the TC, STC, approval of changes or approval of repair designs.
4.4 Statement
The data and information (including instructions) should contain a statement
showing the CAA’s approval.
5. Obligations addressed in 21.A.44 (TC holder), 21.A.118A (STC holder) or 21.A.451 (major
repair design approval holder)
The applicant for alternative procedures to demonstrate their design capabilities should
establish the necessary procedures to show to the CAA how it will fulfil the obligations that
are required under 21.A.44, 21.A.118A or 21.A.451, as appropriate.
6. Control of design subcontractors
The applicant for alternative procedures to demonstrate their design capabilities should
establish the necessary procedures to show to the CAA how it will control design
subcontractors and ensure the acceptability of the parts or appliances that are designed,
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