Page 165 - UK Regulation Part 21 Initial Airworthiness Annex I (consolidated) March 2022

PART 21 - INITIAL AIRWORTHINESS (ANNEX I)

In such a case, the FTOM (or another document) should contain a defined method that
addresses the following points if the (FC) are approved under the DOA privileges:
- FC that must be complied with to safely perform a flight must be determined in
accordance with point 21.A.708;
- management of the aircraft configuration, including the handling of changes to the
aircraft configuration operated under a PtF;
- the documentation of substantiations of flight conditions;
- approval under the privilege using CAA Form 18A defined in AMC 21.A.263(c)(6),
and the definition of the authorised signatories.
For a PtF that is issued under the privilege, a method should be defined that addresses
the following points:
- how conformity with the approved conditions is established, documented and
attested;
- the issue of the PtF under the DOA privilege (form), and the authorised signatories;
- the interface with the local authority for the flight.
Further guidance is provided in AMC 21.A.263(c)(6) and (c)(7), as well as in the GM and
AMC related to Subpart P.
21.A.263(c)(1) AMC1 Procedure for the classification of changes to a type certificate (TC) or to a supplemental type certificate
(STC) and of repair designs as ‘minor’ or ‘major’
1. INTENT
This AMC provides the means to develop a procedure for the classification of changes to
a TC, APU UKTSO or to that part of the product covered by an STC, and repair designs.
Each design organisation approval (DOA) applicant should develop its own internal
classification procedure following this AMC in order to obtain the associated privilege
under 21.A.263(c)(1).
2. PROCEDURE FOR THE CLASSIFICATION OF CHANGES TO A TC, APU UKTSO, OR
TO THAT PART OF THE PRODUCT COVERED BY AN STC, AND REPAIR DESIGNS
2.1 Content
The procedure should address the following points:
- the identification of changes to a TC, APU UKTSO or to that part of the
product covered by an STC, and repair designs,
- classification,
- justification of the classification,
- authorised signatories, and
- supervision of changes to a TC, APU UKTSO or to that part of the product
covered by an STC, and repair designs initiated by subcontractors.
For changes to a TC, APU UKTSO or to that part of the product covered by an STC,
the criteria used for the classification should be in compliance with point 21.A.91 as
further explained in GM 21.A.91.
For repairs, the criteria used for the classification should be in compliance with point
21.A.435 as further explained in GM 21.A.435(a).
2.2 Identification of changes to a TC, APU UKTSO or to that part of the product covered
by an STC, and repair designs
The procedure should indicate how the following are identified:
- major changes to a TC, APU UKTSO or to that part of the product covered by
an STC or major repairs;
- those minor changes to a TC, APU UKTSO or to that part of the product
covered by an STC or minor repairs where additional work is necessary to
demonstrate compliance with the applicable CSs and environmental
protection requirements; and
- other minor changes to a TC, APU UKTSO or to that part of the product
covered by an STC or minor repairs that require no further demonstration of
compliance.
2.3 Classification
The procedure should show how the effects on airworthiness as well as on
operational suitability and environmental protection are analysed, from the very
beginning, by reference to the applicable requirements.
If no specific CS or environmental protection requirements are applicable to the
change or repairs, the above review should be carried out at the level of the part or
system where the change or repair is integrated and where specific CS or
environmental protection requirements are applicable.
2.4 Justification of the classification
All decisions on the classification of changes to a TC, APU UKTSO or to that part of
the product covered by an STC, and repair designs as ‘major’ or ‘minor’ should be
recorded and, for those which are not straightforward, also documented. These
records should be easily accessible to the CAA for sample checking.
2.5 Authorised signatories
All classifications of changes to a TC, APU UKTSO or to that part of the product
covered by an STC, and repair designs should be accepted by an appropriately
authorised signatory, belonging to or tasked by the Office of Airworthiness, as
explained in GM No 1 to 21.A.239(a)(3.1.4)(r).
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