Page 169 - UK Regulation Part 21 Initial Airworthiness Annex I (consolidated) March 2022

PART 21 - INITIAL AIRWORTHINESS (ANNEX I)

21.A.263(c)(5);(8);(9) AMC1 Scope and criteria
1. Definition of ‘certain major repairs’
‘Certain major repairs’ for which privileges may be granted as per point 21.A.263(c)(5) are:
a) major repairs to products or auxiliary power units (APUs) for which the design
organisation approval (DOA) holder holds the type certificate (TC) or the
supplemental type certificate (STC) or the UK technical standard order authorisation
(UKTSOA); or
b) major repairs to products or APUs for which the DOA holder does not hold the TC
or the STC or UKTSOA and that meet the criteria of 3(a), (b) and (c) below.
1.1 Criteria for limitations on eligibility
A CAA approval may be required in cases of major repairs proposed by DOA
holders who are the TC, STC or APU UKTSOA holders if the major repair is:
(a) related to a new interpretation of any item of the certification basis as
used for the type certification (such as the certification specifications
(CSs), certification review items (CRIs) for special conditions,
equivalent safety findings, deviations or ‘elect to comply’); and
(b) related to the application of a CS that is different from the one used for
type certification. Note: This should be established at the time of
granting the privilege to the DOA holder, or later through a CAA-agreed
procedure.
2. Definition of ‘certain major changes’ and ‘certain supplemental type certificates’
‘Certain major changes’ and ‘certain supplemental type certificates’ for which privileges
may be granted as per point 21.A.263(c)(8) and (9) are changes similar to those that have
been previously approved by the CAA for the same DOA holder.
The similarity of the changes is to be seen in terms of the design, the installation, and the
operational characteristics, whereas their repetitiveness is seen in terms of the applicable
requirements and the compliance demonstration.
In this context, a ‘requirement’ means any element of the typecertification basis as
specified in point 21.B.80, or the operational suitability data (OSD) certification basis as
specified in point 21.B.82, or the environmental protection requirements as specified in
point 21.B.85.
2.1 Criteria for limitations on eligibility
The following types of changes are not eligible:
(a) changes that require a revision to a type certificate data sheet (TCDS)
(e.g. the introduction of a derivative model or variant) or a type
certificate data sheet for noise (TCDSN);
(b) changes that require an amendment to the existing certification basis
by a special condition, equivalent safety finding, deviation or ‘elect to
comply’;
(c) changes that revise airworthiness limitations or operating limitations,
unless otherwise agreed with CAA;
(d) changes that are intended to be used as alternative method of
compliance (AMOC) to an airworthiness directive (AD);
(e) changes that are made mandatory by an AD or that are the terminating
action of an AD;
(f) changes that are classified as ‘significant’ in accordance with point
21.A.101;
(g) changes for which, in the affected area and for the operations for which
the design is to be certified, more conservative certification
requirements are applicable which were not used in the description of
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