Page 100 - UK Regulation Part 21 Initial Airworthiness Annex I (consolidated) March 2022

PART 21 - INITIAL AIRWORTHINESS (ANNEX I)

4. General description of facilities
5. General description of production means
6. Human resources
21.A.125A Issue of a letter of agreement
The applicant shall be entitled to have a letter of agreement issued by the CAA agreeing to the
showing of conformity of individual products, parts and appliances under this Subpart, after:
(a) having established a production inspection system that ensures that each product, part or
appliance conforms to the applicable design data and is in condition for safe operation;
(b) having provided a manual that contains:
1. a description of the production inspection system required under point (a);
2. a description of the means for making the determination of the production inspection
system;
3. a description of the tests required in points 21.A.127 and 21.A.128, and the names
of persons authorised for the purpose of point 21.A.130(a);
(c) demonstrating that it is able to provide assistance in accordance with points 21.A.3A and
21.A.129(d).
21.A.125A GM1 Letter of agreement – Meaning of individual
‘Individual’ means that each part number or type of item (i.e., product, part or appliance) to be
produced should be specifically referenced, either directly or through a referenced capability list, in the
letter of agreement from the CAA. The letter may also specify any limitation in the production rate.
21.A.125A(b) GM1 Letter of agreement – Contents of the Manual
The manual referred in 21.A.125A(b) should include, at least the following information:
1. Declaration by the applicant of undertaking in respect of
1.1 the requirements defined in Part 21 Section A Subpart F
1.2 the procedures contained in the manual and in the documentation mentioned herein
1.3 every legal provision laid down for the carrying on of the business activities
(statutory declaration).
2. Declaration by the applicant certifying the conformity of the manual to the requirements
defined in Part 21 Section A Subpart F
3. Jobs, power and responsibilities of the accountable personnel
4. Organisation chart, if required by the CAA
5. Description of the resources, including human resources, with an indication of the
personnel qualification criteria
6. Description of location and equipment
7. Description of the scope of work, the production processes and techniques, and
reference to the ‘capability list’
8. Communications with the CAA, and specifically those required by 21.A.125A(c)
9. Assistance and communication with the design approval holder, and the means of
compliance with 21.A.125A(c)
10. Amendments to the Manual
11. Description of the Inspection System (including test, see GM No 2 to 21.A.125A(b), and
21.A.127 and 21.A.128), and the procedures to meet 21.A.126 and associated GM
12. List of suppliers
13. Issuing of the Statement of Conformity and CAA inspection for validation
If the information is listed in the Manual in a different order a cross-reference to the above list should
be made available in the Manual.
21.A.125A(b) GM2 Letter of agreement – Production Inspection System: Functional Tests
All items produced should be subject to inspection to be carried out at suitable phases which permit
an effective verification of conformity with the design data.
These inspections may provide for the execution of tests to measure performances as set out in the
applicable design data.
Considerations of complexity of the item and/or its integration in the next level of production will largely
determine the nature and time for these tests, for example:
- appliances will require full functional testing to the specifications
- parts will at least require basic testing to establish conformity, but due allowance may be
made for further testing carried out at the next level of production
- material will require verification of its stated properties.
21.A.125A(c) GM Letter of agreement – Assistance
The CAA should be provided with material which defines the means of providing assistance as
required by 21.A.125A(c). Suitable descriptive material should be included in the Manual, as described
in GM No 1 to 21.A.125A(b).
21.A.125B Findings
(a) When objective evidence is found showing non-compliance of the holder of a letter of
agreement with the applicable requirements of this Annex I (Part 21), the finding shall be
classified as follows:
1. a level one finding is any non-compliance with this Annex I (Part 21) which could
lead to uncontrolled non-compliances with applicable design data and which could
affect the safety of the aircraft;
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