Page 172 - UK Regulation Part 21 Initial Airworthiness Annex I (consolidated) March 2022

PART 21 - INITIAL AIRWORTHINESS (ANNEX I)

TC, STC or APU UKTSOA DOA holders that intend to approve a major repair design
under the privilege of point 21.A.263(c)(5) should ensure that:
(a) the type-certification basis for the product, part or appliance to be repaired is
identified, together with all the other relevant requirements;
(b) all the records and substantiation data, including the documents that demonstrate
compliance with all the relevant requirements, are provided to the CAA for review;
and
(c) for repair designs created for a specific product serial number, an assessment is
made as to whether or not the repair design is affected by the presence of any
embodied STC, change or repair.
4. DOA HOLDER’S APPROVAL BASED ON THE PRIVILEGE FOR A MAJOR REPAIR,
MAJOR CHANGE OR STC - SPECIFIC CONSIDERATIONS
For the approval of:
- major repairs by DOA holders that are not the TC, STC or APU UKTSO
authorisation holders;
- major changes; and
- STCs
by a DOA holder under the privilege of point 21.A.263(c)(5), (8) and (9), the following
should be considered.
4.1 Eligibility of the proposed major repair, major change or STC
The DOA holder should assess the proposed major repair, major change or STC
against the ‘list associated with the privilege’ and the ‘justification document’ of
‘certain major repairs’, ‘certain major changes’ or ‘certain supplemental type
certificates’ in order to determine whether the criteria of AMC No1 to 21.A.263(c)(5),
(8) and (9), Section 2.2, are met.
4.2 Forms for approval certificates
The DOA holder should use the following forms for the issuance of an approval
under their privilege:
- CAA Form 991¹ for an STC;
- CAA Form 993¹ for a major change; and
- CAA Form 994¹ for a major repair.
If the DOA holder chooses to use their own forms, it must be ensured that at least
the same information as requested on the CAA forms is presented.
For the numbering of major changes to TCs, STCs, as well as of major repairs
approved under the privilege of point 21.A.263(c)(5), (8) or (9), please refer to GM
21.A.263(c)(5), (8) and (9).
4.3 Approval under the DOA holder’s privilege
When the DOA holder makes use of the privilege of point 21.A.263(c)(5), (8) or (9),
they should include the following in the certification data package:
- a record of the assessment as described in 4.1 above;
- the reference to the ‘justification document’;
- the applicable product configuration;
- the applicable CSs or environmental protection requirements and methods of
compliance;
- the compliance documents;
- the effects, if any, on limitations and on the approved documentation;
- the evidence of the independent checking of the compliance demonstration;
- the approval document containing the statement of the approval under the
privilege of point 21.A.263(c)(5), (8) and (9) by an authorised signatory; and
- the date of approval.
In any case, before the major change, STC or major repair is approved under the
DOA privilege, the DOA holder should ensure that the Part 21 requirements, in
particular points 21.A.97, 21.A.115 and 21.A.433, are met.
4.4 Authorised signatories
An authorised person that is identified and authorised as described in Section 1(b)
(4) above should sign the approval under the privilege of point 21.A.263(c)(5), (8)
and (9).
4.5 Summary list
The DOA holder should add to the ‘summary list’ as described in Section 1(b)(4)
above the major change, STC or major repair approved under the privilege of point
21.A.263(c)(5), (8) and (9).

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