21L.A.61 Scope

Regulation (EU) 2022/1358

This Subpart establishes:

(a) the procedure for applying for the approval of changes to type certificates for products certified in accordance with this Annex, provided that the changed product is still within the scope of point 21L.A.21;

(b) the rights and obligations of the applicants for, and holders of, those approvals referred to in point (a);

(c) provisions regarding the standard changes that do not require an approval.

GM1 21L.A.61 Scope

ED Decision 2023/013/R

The term ‘changes to the type certificate’ is consistently used in Subparts D and E of Part 21 Light, as well as in the related AMC and GM. This term does not refer to changing the document that reflects the type certificate (TC) but to changing the elements of the TC as defined in point 21L.B.47(b). Therefore, the processes contained in Subparts D and E of Part 21 Light should be used for the approval of changes to the elements listed in point 21L.B.47(b).

21L.A.62 Standard changes

Regulation (EU) 2022/1358

(a) Standard changes are those changes to a type certificate of a product approved in accordance with Subpart B of Section B of this Annex:

1. that follow the design data included in the certification specifications issued by the Agency, containing the acceptable methods, techniques and practices for carrying out and identifying standard changes, including the associated instructions for continued airworthiness; and

2. that are not in conflict with the data of the holder of that type certificate.

(b) Points 21L.A.63 to 21L.A.70 are not applicable to standard changes.

GM1 21L.A.62 Standard changes

ED Decision 2023/013/R

APPLICABLE CERTIFICATION SPECIFICATIONS

CS-STAN⁸²https://www.easa.europa.eu/en/certification-specifications/cs-stan-stan… contains the certification specifications referred to in point 21L.A.62. Guidance on the implementation of Standard Changes and Standard Repairs may be found in AMC M.A.801 of the AMC to Part‑M.

21L.A.63 Classification of changes to a type certificate

Regulation (EU) 2022/1358

(a) Changes to a type certificate shall be classified as minor or major.

(b) A ‘minor change’ is a change that has no appreciable effect on the mass, balance, structural strength, reliability, certified noise or emissions levels, operational characteristics, or other characteristics affecting the airworthiness or the environmental compatibility of the product.

(c) All other changes are ‘major changes’, unless the change in design, power, thrust, or mass is so extensive that a substantially complete investigation of compliance with the applicable type‑certification basis or with the applicable environmental protection requirements or with the applicable detailed technical specifications is required, in which case the design shall be certified in accordance with Subpart B of this Annex.

(d) The requirements for the approval of minor changes are those established in point 21L.A.67.

(e) The requirements for the approval of major changes are those established in point 21L.A.68.

AMC1 21L.A.63(c) Classification of changes to a type certificate

ED Decision 2023/013/R

Major changes that are classified as being ‘substantial’ will require a new application for a type certificate in accordance with Subpart B of Part 21 Light.

Examples of major changes that are considered substantial may be found in Appendix B to GM1 21L.A.63.

GM1 21L.A.63 Classification of changes to a type certificate

ED Decision 2023/013/R

(a) PURPOSE OF CLASSIFICATION

The purpose of classification of changes to a type certificate (TC) into ‘minor’ or ‘major’ is to determine the approval route to be followed in accordance with Part 21 Light Subpart D, i.e. either point 21L.A.67 or point 21L.A.68, or alternatively whether application and approval have to be made in accordance with Part 21 Light Subpart E.

(b) INTRODUCTION

(1) Point 21L.A.63 proposes criteria for the classification of changes to a TC as ‘minor’ or ‘major’.

(i) This GM is intended to provide guidance on the term ‘appreciable effect’ that affects the airworthiness of the product, the certified noise or emissions levels or affects any of the other characteristics mentioned in point 21L.A.63, where ‘airworthiness’ is interpreted in the context of a product that is in conformity with type design and in condition for safe operation. It provides complementary guidelines to assess a change to the TC in order to meet the requirements of points 21L.A.63 and 21L.A.91 where classification is the first step of a procedure.

Characteristics that affect the environmental compatibility of the product are characteristics that affect the compliance of the product with the applicable environmental protection requirements.

Note: For the classification of repairs, see GM 21L.A.203(a).

(ii) Although this GM provides guidance on the classification of major changes, as opposed to minor changes as defined in point 21L.A.63, the GM and point 21L.A.63 are deemed entirely compatible.

Appendix A to GM1 21L.A.63 provides examples of major changes and a classification process.

(c) ASSESSMENT OF A CHANGE FOR CLASSIFICATION

(1) Changes to the TC

Point 21L.A.63 addresses all changes to any of the aspects of a TC. This includes changes to a type design, as defined in point 21L.A.26, as well as to the other constituents of a TC, as defined in point 21L.B.47(b).

(2) Reserved

(3) Classification process (see also the flow chart ‘Classification process’ in Appendix A to GM1 21L.A.63)

Point 21L.A.63 requires all changes to be classified as either ‘major’ or ‘minor’, using the criteria of point 21L.A.63.

Wherever there is doubt as to the classification of a change, EASA should be consulted for clarification.

When the strict application of the point (c)(4) criteria results in a major classification, the applicant may request reclassification, if justified, and EASA could take the responsibility for reclassifying the change.

A simple design change planned to be mandated by an airworthiness directive may be reclassified as minor due to the involvement of EASA in the continued airworthiness process when this is agreed between EASA and the design organisation.

The reasons for a classification decision should be recorded.

(4) General guidance on the classification of major changes

A change to the TC that is judged to have an ‘appreciable effect on the mass, balance, structural strength, reliability, certified noise or emissions levels, operational characteristics, or other characteristics affecting the airworthiness or the environmental compatibility’ is classified as major, in particular, but not only, when one or more of the following conditions are met:

(i) where the change requires an adjustment of the type-certification basis (special conditions or equivalent safety findings) other than electing to comply with later certification specifications or an adjustment to the applicable environmental protection requirements (e.g. when a new requirement becomes applicable after the type certification);

(ii) where the applicant proposes a new interpretation of the certification specifications used for the type-certification basis that has not been published as AMC material or otherwise agreed with EASA;

(iii) where the demonstration of compliance uses methods that have not been previously accepted as appropriate for the nature of the change;

(iv) where the extent of new substantiation data necessary to comply with the applicable certification specifications and the degree to which the original substantiation data has to be reassessed and re-evaluated is considerable;

(v) where the change alters the airworthiness limitations or the operating limitations;

(vi) where the change is made mandatory by an airworthiness directive or the change is the terminating action of an airworthiness directive (ref. point 21L.A.4), see Note 1; and

(vii) where the design change introduces or affects functions where the failure effect is classified as catastrophic or hazardous.

Note 1: A change previously classified as minor and approved prior to the decision to issue an airworthiness directive needs no reclassification. However, EASA retains the right to review the change and reclassify/reapprove it if found necessary.

Note 2: The conditions listed in points (i) through (vii) above are an explanation of the criteria noted in point 21L.A.63, and of point 21L.A.103 that refers to this point for the classification of changes in Subpart F.

For an understanding of how to apply the above conditions, it is useful to take note of the examples given in Appendix A to GM1 21L.A.63.

(5) Guidance on the classification of changes to aircraft flight manuals (AFMs)

The following changes to the AFM are deemed to be minor:

(i) revisions to the AFM associated with changes to the type design that are classified as minor in accordance with point 21L.A.63;

(ii) revisions to the AFM that are not associated with changes to the type design (also identified as stand-alone revisions) which fall into one of the following categories:

(A)  changes to limitations or procedures that remain within already certified limits (e.g. weight, structural data, etc.);

(B)  consolidation of two or more previously approved and compatible AFMs into one, or the compilation of different parts taken from previously approved and compatible AFMs that are directly applicable to the individual aircraft (customisation); and

(C) the introduction into a given AFM of compatible and previously approved AFM amendments, revisions, appendices or supplements; and

(D) changes that affect the certified noise or emissions levels of the product; and

(iii) administrative revisions to the AFM, defined as follows:

(A) for the AFMs issued by the TC holder:

(a) editorial revisions or corrections to the AFM;

(b) changes to parts of the AFM that do not require approval by EASA;

(c) conversions of previously Federal Aviation Administration (FAA)- or EASA-approved combinations of units of measurement added to the AFM in a previously approved manner;

(d) the addition of aircraft serial numbers to an existing AFM where the aircraft configuration, as related to the AFM, is identical to the configuration of the aircraft already covered by that AFM;

(e) the removal of references to aircraft serial numbers no longer applicable to that AFM; and

(f) the translation of an EASA-approved AFM into the official language of the State of design or State of registry;

(B) for AFM supplements issued by STC holders:

(a) editorial revisions or corrections to the AFM supplement;

(b) changes to parts of the AFM supplement that are not required to be approved by EASA;

(c) conversions of previously FAA- or EASA-approved combinations of units of measurement added to the AFM supplement in a previously approved manner;

(d) the addition of aircraft serial numbers to an existing AFM supplement where the aircraft configuration, as related to the AFM supplement, is identical to that of the aircraft already in that AFM supplement; ‘identical’ means here that all aircraft must belong to the same type and model/variant;

(e) the addition of a new STC to an existing AFM supplement, when this supplement is fully applicable to the new STC;

(f) the removal of references to aircraft serial numbers that are no longer applicable to that AFM supplement;

(g) the translation of an EASA-approved AFM supplement into the official language of the State of design or State of registry.

(6) Guidance on the classification of changes to certified aircraft noise levels and aircraft engine emissions levels

Volumes I and II of ICAO Doc 9501 ‘Environmental Technical Manual’ define ‘no-acoustical changes’ and ‘no-emissions changes’ respectively as changes that would result in very small changes in the certified levels and provide criteria for their determination. These changes have ‘no appreciable effect’ on the certified levels. Consequently, they are classified as minor changes for environmental protection and the certified levels remain unchanged.

If the ‘no-acoustical change’ or ‘no-emissions change’ is demonstrated using an equivalent procedure to the one specified in ICAO Annex 16, the applicant should seek the agreement of EASA on the classification of the change. An equivalent procedure is a test or analysis procedure which, while differing from the one specified in ICAO Annex 16, effectively yields the same noise or emission levels as the specified procedure according to the technical judgement of EASA.

All other changes to the certified aircraft noise levels and aircraft engine emissions levels are classified as major changes.

Examples of major changes are provided in Appendix A to GM1 21L.A.63.

Appendix A to GM1 21L.A.63 Classification of changes to a type certificate

ED Decision 2023/013/R

EXAMPLES OF MAJOR CHANGES PER DISCIPLINE

The information below is intended to provide a few examples of major changes per discipline, resulting from the application of point 21L.A.63 and point 3.3 below. It is not intended to present a comprehensive list of all major changes. Examples are categorised per discipline and are applicable to all products (aircraft, engines, propellers). However, a particular change may involve more than one discipline, e.g. a change to engine controls may be covered in engines and systems (software).

Those involved in the classification of changes should always be aware of the interaction between disciplines and the consequences this will have when assessing the effects of a change (i.e. operations and structures, systems and structures, systems and systems, etc.).

Specific rules may exist which override the guidance of these examples.

In Part 21 Light, a negative definition is given of minor changes only. However, in the following list of examples, it was preferred to give examples of major changes.

Where in this list of examples the words ‘has effect’ or ‘affect(s)’ are used, they have always to be understood as being the opposite of ‘no appreciable effect’ as in the definition of minor change in point 21L.A.63. Strictly speaking, the phrases ‘has appreciable effect’ and ‘appreciably affect(s)’ should have been used, but this has not been done to improve readability.

1. Structure

(i) Changes such as a change of dihedral, addition of floats.

(ii) Changes to materials, processes or methods of manufacture of primary structural elements, such as spars, frames and critical parts.

(iii) Changes that adversely affect fatigue or damage tolerance or life-limit characteristics.

(iv) Changes that adversely affect aeroelastic characteristics.

2. Cabin safety

(i) Changes which introduce a new cabin layout of sufficient change to require a reassessment of the emergency evacuation capability, or changes which adversely affect other aspects of passenger or crew safety.

Items to consider include but are not limited to:

—       changes to or introduction of dynamically tested seats;

—       changes to cabin layouts that affect evacuation path or access to exits;

—       changes to the cabin area in striking distance of the occupant’s head or torso introducing potentially injurious objects

3. Flight

Changes which adversely affect the approved performance or brake changes that affect braking performance.

Changes which adversely affect the flight envelope.

Changes which adversely affect the handling qualities of the product, including changes to the flight controls function (gains adjustments, functional modification to software), or changes to the flight protection or warning system.

4. Systems

For systems assessed under CS 23.2510, the classification process is based on the functional aspects of the change and its potential effects on safety.

(i) Where the failure effect is ‘catastrophic’ or ‘hazardous’, the change should be classified as ‘major’.

(ii) Where the failure effect is ‘major’, the change should be classified as ‘major’ if:

—       aspects of the compliance demonstration will use a means that has not been previously accepted for the nature of the change to the system; or

—       the change affects the pilot–system interface (displays, controls, approved procedures); or

—       the change introduces new types of functions/systems such as GPS primary, TCAS, predictive windshear, HUD.

The assessment of the criteria for software changes to systems should also be performed.

When software is involved, account should be taken also of the following guidelines:

Where a change is made to software produced in accordance with the guidelines of the latest edition of AMC 20-115 (see AMC‑20 document), the change should be classified as ‘major’ if either of the following applies, and the failure effect is ‘catastrophic’, ‘hazardous’ or ‘major’:

(i) the executable code for software, determined to be Level A or Level B in accordance with the guidelines, is changed unless that change involves only a variation of a parameter value within a range already verified for the previous certification standard; or

(ii) the software is upgraded to or downgraded from Level A, Level B or Level C; or

(iii) the executable code, determined to be level C, is deeply changed, e.g. after a software re-engineering process accompanying a change of processor.

For software developed to guidelines other than the latest edition of AMC 20‑115, the applicant should assess the changes in accordance with the foregoing principles.

For other codes, the principles noted above may be used. However, due consideration should be given to specific certification specifications/interpretations.

For example:

—       Opening and listening on a User Datagram Protocol (UDP) port in an end system of an already certified topology.

—       Activating a protocol in a point-to-point communication channel.

—       The modification of a service between a system of a more closed, controlled security domain and a system of a more open, less controlled security domain.

—       The modification of a security control between a system of a more closed, controlled information security domain and a system of a more open, less controlled security domain.

5. Propellers

Changes to:

—       diameter,

—       aerofoil,

—       planform,

—       material,

—       blade retention system, etc.

6. Engines

Changes:

(i) that adversely affect operating speeds, temperatures, and other limitations;

(ii) that affect or introduce parts identified by CS E-510 where the failure effect has been shown to be ‘hazardous’;

(iii) that affect or introduce engine critical parts (CS E-515) or their life-limits.

(iv) to a structural part which requires a resubstantiation of the fatigue and static load determination used during certification;

(v) to any part of the engine which adversely affects the existing containment capability of the structure;

(vi) that adversely affect the fuel, oil and air systems, which alter the method of operation, or require reinvestigation against the type-certification basis;

(vii) that introduce new materials or processes, particularly on critical components.

7. Rotors and drive systems

Changes that:

(i) adversely affect fatigue evaluation unless the service life or inspection interval is unchanged; this includes changes to materials, processes or methods of manufacture of parts, such as

—       rotor blades,

—       rotor hubs including dampers and controls,

—       gears,

—       drive shafts,

—       couplings;

(ii) affect systems whose failure may have ‘hazardous’ or ‘catastrophic’ effects; the design assessment should include:

—       the cooling system,

—       the lubrication system,

—       rotor controls;

(iii) adversely affect the results of the rotor drive system endurance test, the rotor drive system being defined in CS 27.917;

(iv) adversely affect the results of the shafting critical speed analysis required by CS 27.931.

8. Noise and emissions

The examples provided below are not exhaustive and will not, in every case, result in an appreciable effect on the certified noise or emissions levels and, therefore, will not per se and in every case result in a major change classification.

(i) Examples of noise-related changes that might lead to a major change classification are:

(1) for propeller-driven aeroplanes:

—       a change that might affect the aircraft’s take-off performance, including:

—       a change to the maximum take-off mass;

—       a change to the take-off distance;

—       a change to the rate of climb; or

—       a change to V_Y (best rate of climb speed);

—       a change that increases the aircraft’s drag (e.g. the installation of external cargo pods, external fuel tanks, larger tyres to a fixed undercarriage, floats etc.);

—       a change of engine or propeller type;

—       a change in take-off power including a change in engine speed (tachometer ‘red line’) or, for piston engines, a change to the manifold pressure limitations;

—       a change to the highest power in the normal operating range (‘top of green arc’);

—       in the case of an aircraft where take-off power/engine speed is time limited, a change in the period over which take-off power/engine speed may be applied;

—       a change to the engine inlet or exhaust including, if fitted, the inlet or exhaust muffler;

—       a change in propeller diameter, tip shape, blade thickness or the number of blades;

—       the installation of a variable or adjustable pitch propeller in place of a fixed pitch propeller and vice versa;

—       a change that causes a change to the angle at which air flows into the propeller;

(2) for helicopters:

—       a change that might affect the take-off and/or landing performance, including a change in take-off mass and V_Y (best rate of climb speed);

—       a change to VNE (never-exceed airspeed) or to VH (airspeed in level flight obtained using the torque corresponding to minimum engine installed, maximum continuous power available for sea level pressure, 25°C ambient conditions at the relevant maximum certified mass);

—       a change to the maximum take-off engine power or maximum continuous power;

—       a change to the gearbox torque limits;

—       a change of engine type;

—       a change to the engine intake or exhaust;

—       a change to the maximum normal operating rpm of the main or tail rotors;

—       a change to the main or tail rotors, including a change in diameter, blade thickness or blade tip profile.

Note: The effect on the helicopter’s noise characteristics of either carrying external loads or the installation of external equipment need not be considered.

(ii) Examples of smoke-engine-emissions-related changes that might lead to a major change classification are:

—       a change in engine thrust rating;

—       a change to the aerodynamic flow lines through the engine;

—       a change that affects the engine thermodynamic cycle, specifically relevant engine cycle parameters (e.g. combustor pressure P3, combustor entry temperature T3, air fuel ratio (AFR));

—       a change to the compressor that might influence the combustor inlet conditions and engine overall pressure ratio;

—       a change to the combustor design (geometry);

—       a change to the cooling of the combustor;

—       a change to the air mass flow through the combustor;

—       a change that affects the fuel spray characteristics.

9. Power plant installation

Changes which include:

(i) control system changes which affect the engine/propeller/airframe interface;

(ii) new instrumentation displaying operating limits;

(iii) modifications to the fuel system and tanks (number, size and configuration);

(iv) change of engine/propeller type.

10. Stand-alone changes to non-ALS ICAs that require additional work to demonstrate compliance with the applicable certification basis as follows:

(i) the introduction of novel technology for inspection purposes related to an ALS task;

(ii) changes that adversely affect the certification assumptions: e.g. some specific inspection procedures, such as inspection procedures for use after a hard landing, may include a decision-making chart based on the level of exceedance of the load in comparison with the certified limit loads; such criteria, and adverse changes, should be agreed with EASA.

Classification process

Appendix B to GM 21L.A.63 Classification of changes to a type certificate

ED Decision 2023/013/R

The following tables provide examples of ‘substantial’ changes. The classification may change due to cumulative effects and/or combinations of individual changes.

A.1 Examples of ‘substantial’ changes for small aeroplanes (CS-23)

A.1.1 Table A-1 contains examples of changes that are ‘substantial’ for small aeroplanes (CS-23).

Table A-1 — Examples of ‘substantial’ changes for small aeroplanes (CS-23)

A.2 Examples of ‘substantial’ changes for rotorcraft (CS-27)

A.2.1 Table A-2 contains examples of changes that are ‘substantial’ for rotorcraft (CS-27).

Table A-2 — Examples of ‘substantial’ changes for rotorcraft (CS-27)

A.3 Examples of ‘substantial’ changes for propellers (CS-P)

A.3.1 Table A-3 contains an example of a change that is ‘substantial’ for propellers (CS-P).

Table A-3 — Example of a ‘substantial’ change for propellers (CS-P)

21L.A.64 Eligibility

Regulation (EU) 2022/1358

(a) Only the type-certificate holder may apply for the approval of a major change to a type certificate under this Subpart; all other applicants for a major change to a type certificate shall apply under Subpart E of this Annex.

(b) Any natural or legal person may apply for the approval of a minor change to a type certificate under this Subpart.

21L.A.65 Application for a change to a type certificate

Regulation (EU) 2022/1358

(a) An application for the approval of a change to a type certificate shall be made in a form and manner established by the Agency.

(b) For a major change to a type certificate, the applicant shall include in the application a compliance demonstration plan for the demonstration of compliance in accordance with point 21L.A.66, along with a proposal for the type-certification basis and the applicable environmental protection requirements, prepared in accordance with the requirements and options specified in point 21L.B.81.

AMC1 21L.A.65 Application for a change to a type certificate

ED Decision 2023/013/R

FORM AND MANNER

The applicant should file an application using the web-based ‘EASA Applicant Portal’⁸³https://ap.easa.europa.eu (accessed: DD.MM.2023) or the application forms for the approval of major changes/major repair designs or for the approval of minor changes/minor repair designs, which may be downloaded from the EASA website.

The forms should be completed in accordance with the instructions embedded at the bottom of the application forms, and sent to EASA by fax, email or regular mail following the information provided on the EASA website⁸⁴https://www.easa.europa.eu/document-library/application-forms/certifica… (accessed: 20 October 2023).

AMC1 21L.A.65(b) Application for a change to a type certificate

ED Decision 2023/013/R

CERTIFICATION BASIS

Point 21L.A.65(b) ‘a proposal for the type-certification basis and the applicable environmental protection requirements, prepared in accordance with the requirements and options specified in point 21L.B.81’.

The proposed type-certification basis should include applicable certification specifications, proposed special conditions, proposed equivalent safety findings, as well as a proposed ‘elect to comply’ and proposed deviations, as applicable.

21L.A.66 Demonstration of compliance

Regulation (EU) 2022/1358

(a) The applicant for a major change to a type certificate shall demonstrate compliance with the applicable type-certification basis and the applicable environmental protection requirements as established and notified to the applicant by the Agency in accordance with point 21L.B.81, and shall provide the Agency with the means by which such compliance has been demonstrated.

(b) The applicant for a major change to a type certificate shall provide the Agency with a recorded justification of the means of compliance according to the compliance demonstration plan.

(c) When carrying out testing and inspections to demonstrate compliance in accordance with point (a), the applicant shall have verified and documented this verification prior to carrying out any test:

1. for the test specimen, that:

(i) the materials and processes adequately conform to the specifications for the proposed changed type design;

(ii) the constituent parts of the products adequately conform to the drawings in the proposed changed type design;

(iii) the manufacturing processes, construction and assembly adequately conform to those specified in the proposed changed type design; and

2. that the test and measuring equipment used for the test were adequate for the test and appropriately calibrated.

(d) The flight testing for the purpose of obtaining an approval of a major change to a type certificate shall be conducted in accordance with the methods for such flight testing specified by the Agency. The applicant for a major change to a type certificate shall make all the flight tests necessary to determine compliance with the applicable type-certification basis and the applicable environmental protection requirements.

(e) An applicant for a major change to a type certificate shall allow the Agency to:

1. review any data and information related to the demonstration of compliance;

2. witness or carry out any test or inspection conducted for the purpose of the demonstration of compliance; and

3. if it is considered necessary, conduct a physical inspection of the first article of that product in the final changed configuration to verify the compliance of the design with the type‑certification basis and the applicable environmental protection requirements.

(f) Upon completion of the compliance demonstration, the applicant shall declare to the Agency that:

1. they have demonstrated compliance with the type-certification basis and the applicable environmental protection requirements as established and notified to the applicant by the Agency in accordance with point 21L.B.81, according to the compliance demonstration plan; and

2. no feature or characteristic has been identified that may make the changed product unsafe or environmentally incompatible for the uses for which certification is requested.

AMC1 21L.A.66 Demonstration of compliance

ED Decision 2023/013/R

DEMONSTRATION OF COMPLIANCE FOR A CHANGE TO A TYPE CERTIFICATE

The description of the change should include an explanation of the purpose of the change, the pre-modification and post-modification configuration(s) of the product, schematics/pictures, and any other detailed features and boundaries of the physical change (this may be supplemented by drawings or outlines of the design, if this helps to understand the design change), as well as the identification of the changes in areas of the product that are functionally affected by the change, and the identification of any changes to the approved manuals.

The applicant should identify any reinvestigations that are necessary to demonstrate compliance. This is a list of affected items of the applicable type-certification basis for which a new demonstration is necessary, together with the means (e.g. calculation, test or analysis) by which it is proposed to demonstrate compliance.

Before submitting the application for a change, the analysis and classification activities under point 21L.A.63 should be performed using the corresponding GM. For repair designs, the analysis under point 21L.A.63 should be performed using GM 21L.A.203.

For a major change, AMC1 21L.A.24(b)(4) should be used as applicable to the change for the development of the compliance-demonstration plan.

Compliance documentation for the demonstration of compliance under point 21L.A.66(a) comprises one or more test or inspection programmes/plans, reports, drawings, design data, specifications, calculations, analyses, etc., and provides a record of the means by which compliance with the applicable type-certification basis and environmental protection requirements is demonstrated.

Each compliance document should typically contain:

—      the reference of the certification specifications, special conditions or environmental protection requirements addressed by the document;

—      substantiation data demonstrating compliance (except test or inspection programmes/plans);

—      a statement by the applicant declaring that the document provides the proof of compliance for which it has been created; and

—      the appropriate authorised signature.

Each compliance document should be unequivocally identified by its reference and issue date. The various issues of a document should be controlled and comply with point 21L.A.7.

The level of detail of the compliance documentation that is referred to in point 21L.A.66(a) should be the same regardless of whether the change is approved by EASA or under a design organisation approval (DOA) privilege, to allow the change to be assessed in the frame of the DOA surveillance.

The compliance-demonstration process always takes into account the specific configuration(s) in the type certificate (TC) to which the major change under approval is applied. This (these) configuration(s) may be defined by type models/variants or by design changes to the type design. The demonstration of compliance covers this (these) applicable specific configuration(s). Consequently, the approval of the major change excludes any other configurations, in particular those that already exist but are not considered in the compliance-demonstration process, as well as those that may be certified in the future.

For major changes approved by a design organisation approval (DOA) holder on the basis of its privilege as per point 21.A.263(c)(8) of Annex I (Part 21), the process described under AMC No 2 to 21.A.263(c)(5), (8) and (9) applies.

AMC1 21L.A.66(c) Demonstration of compliance

ED Decision 2023/013/R

INSPECTIONS AND TESTS

Proposed type design: this term defines the type design (or the portion of the type design) as it is determined at the time when the testing and inspections are carried out.

Verification document (also known as ‘statement of conformity’): before each testing and inspection, the verification document must confirm that the test specimen conforms with the proposed design, the test and measuring equipment is adequate for the test, and the sensors and measuring system are appropriately calibrated.

Conformity of the test specimen: the documented verification is intended to ensure that the manufactured test specimen adequately represents the proposed type design. Possible types of non-conformity may be the following:

—      Non-conformity between the design of the test specimen and the proposed type design at the time of the test. These are typically identified in the early stage of the testing and inspection planning, and should be addressed as early as possible (e.g. in the test plan). There may be several reasons for such a non-conformity: to account for interfaces with the test equipment, to conservatively cover several or future design configurations, etc.

—      Non-conformity between the manufactured test specimen and the design of the test specimen. Such a non-conformity may be the result of the manufacturing of the test specimen.

While it is convenient to define any possible non-conformity in as early as possible, the applicant does not need to make the distinction between the two types of non-conformity above as long as they are explicitly addressed, justified in the verification document or by cross reference to the test plan or other documents. However, testing for the demonstration of compliance with the applicable environmental protection requirements should be conducted in the final design of the product having incorporated the change.

Certification is typically an iterative process in which the design is under continuous evolution. If the type design evolves after the time of the testing and inspections, then the final type design should be checked against the proposed type design (as it was at the time of the testing and inspections), and the differences (if any) should be analysed to ensure that the testing and inspections’ results are representative of the final configuration. However, such changes made to the type design may lead to the invalidation of the testing and inspections’ results and the need to repeat the testing and inspections. It is recommended that the design organisation should have a thorough configuration management process to track the evolving type design.

Conformity of test and measuring equipment: the configuration of the test and measuring equipment should be defined in the test plan and should include the following:

—      definition/design of the test equipment (relevant tools, mechanical parts, electronic components used to execute the test); and

—      definition of the measuring equipment:

—      type/model of sensors, together with their technical characteristics;

—      position and orientation of exciters and sensors; and

—      electronic measuring equipment (in some cases, this may also include the acquisition and post-processing of data).

The configuration of the test and measuring equipment should be defined and controlled through certification test plans and supporting documentation, according to the design assurance system, if applicable. The test plan should also include the following elements:

—      the test cases, methods, and procedures for test execution;

—      the pass–fail criteria; and

—      pre-, during- and post-test inspections.

The verification document should confirm that the test and measuring equipment conforms to its purpose, and that the sensors and measuring system are appropriately calibrated. Any non-conformity should be assessed, and it should be justified that it will not compromise the test purpose and results. This may be done either in the verification document or by cross reference to other documents (test minutes of meetings, test notes, etc.).

Use of the term ‘adequate’: the test specimen, as well as the test and measuring equipment, is considered ‘adequate’ as long as the test execution on the manufactured test specimen (including any non-conformity) and the use of the installed test set-up do not compromise the test purpose and results (for example, by providing better performance than the proposed type design, or masking any potential failure mode or behaviour).

Changes that affect the validity of the verification document: if changes need to be introduced to the test specimen or to the test and measurement equipment after the verification is documented (and before the test is undertaken), then the verification document must be updated. The updated verification document must be made available to EASA before the test if EASA has informed the applicant that it will witness or carry out the tests or inspections.

Development versus certification tests: sometimes, tests on specimens that conform to a preliminary design, but are not intended for certification (known as development tests), are performed as part of a risk control strategy and to develop knowledge of a subject. Problems and failures found during development are part of the process of increasing the understanding of the design, including its failure modes and the potential for optimisation. Such development tests do not need to meet the requirements of point 21L.A.66(c).

Any planned test event should be classified in advance as either a development test or a certification test. Tests that support the compliance demonstration should be classified as certification tests.

It is acceptable for a development test to finally form part of the compliance demonstration, and it may be declared afterwards to be a certification test as long as it meets the requirements of point 21L.A.66(c). For this reason, it is important to keep the configuration of such tests under control.

If the test specimen used for a certification test has already undergone a series of previous tests that may affect or ultimately invalidate its acceptance as required by point 21L.A.66(c), this aspect should be considered when documenting the verification, and specific analyses or inspections may be required.

Because of the above aspects, EASA advises applicants to inform EASA if they intend to conduct a campaign of development tests that may eventually be used as certification tests to establish whether EASA would wish to witness the test(s).

GM1 21L.A.66(d) Demonstration of compliance

ED Decision 2023/013/R

FLIGHT TESTING

Detailed material on flight testing for compliance demonstration is included in the applicable CSs and GM. Information on flight testing for compliance demonstration with the applicable environmental protection requirements may be found in Volumes I, II and III of Annex 16 to the Chicago Convention and in ICAO Doc 9501 ‘Environmental Technical Manual’.

AMC1 21L.A.66(e)(1) Demonstration of compliance

ED Decision 2023/013/R

DATA AND INFORMATION REVIEW

Availability of compliance data (see point 21L.A.66(e)): data and information required to be provided by the applicant should be made available to EASA in a reliable and efficient way.

AMC1 21L.A.66(e)(2) Demonstration of compliance

ED Decision 2023/013/R

TESTS AND INSPECTIONS

The applicant should inform EASA sufficiently in advance about the execution of tests and inspections that:

—      are used for compliance-demonstration purposes; and

—      have been identified as being of particular interest to EASA during the review and approval of the compliance-demonstration plan

in order to permit EASA the opportunity to witness or carry out these inspections or tests.

The applicant may propose to EASA to witness or carry out flight or other tests of particular aspects of the product during its development and before the type design is fully defined.

However, in case of flight tests, the applicant should perform the tests before EASA witnesses or performs them to ensure that no feature of the product precludes the safe conduct of the evaluation requested. EASA may require any such tests to be repeated once the type design is fully defined to ensure that subsequent changes have not adversely affected the conclusions from any earlier evaluation.

A verification document as per point 21L.A.66(c) is required for the above tests.

AMC1 21L.A.66(e)(3) Demonstration of compliance

ED Decision 2023/013/R

FIRST-ARTICLE PHYSICAL INSPECTION

The applicant should be prepared for any additional investigations as notified by EASA according to point 21L.B.83(c).

Refer to AMC1 21L.A.25(e)(3) for an explanation of the activities performed under the first-article inspection.

GM1 21L.A.66(f) Demonstration of compliance

ED Decision 2023/013/R

DECLARATION OF COMPLIANCE

All compliance demonstrations in accordance with the compliance-demonstration plan, including all the testing and inspections in accordance with point 21L.A.66(c) and all flight testing in accordance with point 21L.A.66(d) and those necessary to determine compliance with the applicable environmental protection requirements, should be completed before the issuance of the final declaration of compliance.

‘No feature or characteristic’ that may make the changed product unsafe under point 21L.A.66(f)(2) means the following: while every effort is made to address in the applicable certification basis all the risks to product safety that may be caused by the product, experience shows that safety-related events may occur with products in service, even though compliance with the certification basis is fully demonstrated. One of the reasons may be that some existing risks are not properly addressed in the certification basis. Therefore, the applicant should declare that it has not identified any such feature or characteristic.

‘No feature or characteristic’ that may make the changed product environmentally incompatible under point 21L.A.66(f)(2):

It is assumed that environmental compatibility is demonstrated when the changed product complies with the applicable environmental protection requirements. Therefore, the applicant, when declaring that the changed product complies with the applicable environmental protection requirements under point 21L.A.66(f)(1), should also declare that it has not identified any such feature or characteristic.

21L.A.67 Requirements for the approval of a minor change to a type certificate

Regulation (EU) 2022/1358

In order to be issued with an approval of a minor change to a type certificate, the applicant shall:

(a) demonstrate that the change and the areas affected by the change comply:

1. with the type-certification basis and the applicable environmental protection requirements incorporated by reference in the type certificate; or

2. if the applicant chooses to, with the certification specifications that are applicable to the product on the date of the application for the change;

(b) declare compliance with the type-certification basis and the applicable environmental protection requirements that apply in accordance with point (a)(1), or with the certification specifications chosen in accordance with point (a)(2), record the justifications of compliance in the compliance documents, and record that no feature or characteristic has been identified that may make the changed product unsafe for the uses for which certification is requested;

(c) submit to the Agency the justification of compliance for the change and the declaration of compliance.

AMC1 21L.A.67 Requirements for the approval of a minor change to a type certificate

ED Decision 2023/013/R

(a) Applicability of point 21L.A.67

Point 21L.A.67 should be complied with by applicants for the approval of a minor change to a type certificate (TC), and by design organisation approval (DOA) holders that approve minor changes under their own privileges.

Point 21L.A.67(c), however, only applies to projects for which an application is submitted to EASA. For DOA holders that approve minor changes under their privileges, the justification of compliance and the declaration of compliance required by point 21L.A.67(b) should be produced but do not need to be submitted to EASA. They should be, however, kept on record and submitted to EASA on request during its DOA continued surveillance process.

(b) The approval process

The approval process comprises the following steps:

Note:  Steps 1, 2 and 4 should be followed only by applicants for minor changes approved by EASA. DOA holders that approve minor changes under their privileges should refer to AMC No 1 to 21.A.263(c)(2) or AMC No 2 to 21.A.263(c)(2), as applicable to their approval process.

(1) Application

When the minor change is approved by EASA, an application should be submitted to EASA as described in point 21L.A.65 and in AMC 21L.A.65.

(2) Certification basis

(3) Justification of compliance

(4) Declaration of compliance

(c) Certification basis

The certification basis for a minor change consists of a subset of the elements of the product’s certification basis ‘incorporated by reference in the type certificate’.

The certification basis ‘incorporated by reference in the type certificate’ is the certification basis for the product as recorded in the type certificate data sheet (TCDS) for the product type/model in the applicable configuration(s).

The certification basis contains the applicable airworthiness and environmental protection requirements specified by reference to their amendment level, as complemented by special conditions, equivalent safety findings, deviations, a proposed ‘elect to comply’, etc., as applicable.

By way of derogation from the above, CSs that became applicable after those incorporated by reference in the TC may be used for the approval of a minor change (see the guidance below on certification specifications that became applicable after those ‘incorporated by reference in the type certificate’).

If other changes are required for the embodiment of the minor change, the certification basis corresponding to the product modified by these other changes should also be considered when determining the certification basis for the minor change.

(d) Justification of compliance required by point 21L.A.67(c)

The applicant should justify compliance with the certification basis under point 21L.A.67(a) for all areas that are either physically changed or functionally affected by the minor change.

(1) Means of compliance: the applicant should define and record the means (calculation, test or analysis, etc.) by which compliance is demonstrated. Appendix A to AMC1 21L.A.24(b) may be used to describe how compliance is demonstrated.

(2) Compliance documents: the compliance demonstration should be recorded in compliance documents. For minor changes, one comprehensive compliance document may be sufficient, provided that it contains evidence of all aspects of the compliance demonstration.

See also the additional guidance in point (e) below.

(3) Aircraft manuals: where applicable, supplements to manuals (e.g. aircraft flight manual (AFM), aircraft maintenance manual (AMM), etc.) may be issued.

See also additional guidance in point (f) below on embodiment/installation instructions.

(e) Definition of the change to the type certificate

The change to the type certificate should be defined in accordance with GM 21L.A.61.

(f) Embodiment/installation instructions

The instructions for the embodiment/installation of the change (e.g. service bulletin, modification bulletin, production work order, etc.) should be defined. This may include the installation procedure, the required material, etc.

(g) Certification specifications that are applicable to the product on the date of the application for the change

(1) Minor changes are those changes that do not affect the airworthiness of the product. This means that the certification basis for the minor change may consist of the items of the certification basis incorporated by reference in the TCDS of the product type/model, and normally it should not be necessary for a minor change to use certification specifications that became applicable after those that are incorporated by reference in the type certificate.

(2) On the other hand, the applicant may elect to use the certification specifications that are applicable to the product on the date of the application for the change for the compliance demonstration. This does not affect the classification of the change.

(h) Feature or characteristic that affects the airworthiness or environmental compatibility of the changed product

The term ‘no feature or characteristic’ applies to a minor change, in which case the effect of the change on the product safety or environmental compatibility is quite low. Minor changes should not be approved if either the design organisation approval (DOA) holder approving minor changes under its privileges or EASA is aware of a feature or characteristic that may make the changed product unsafe or environmentally incompatible for the uses for which the approval is requested.

GM1 21L.A.67(c) Requirements for the approval of a minor change to a type certificate

ED Decision 2023/013/R

The level of detail of the justification that is referred to in point 21L.A.67(c) should be the same regardless of whether the change is approved by EASA or under a design organisation approval (DOA) privilege, to allow the change to be assessed in the frame of the DOA surveillance.

21L.A.68 Requirements for the approval of a major change to a type certificate

Regulation (EU) 2022/1358

In order to be issued with an approval of a major change to a type certificate, the applicant shall:

(a) demonstrate that the change and the areas affected by the change comply with the type-certification basis and the applicable environmental protection requirements, as established and notified to the applicant by the Agency in accordance with point 21L.B.81

(b) demonstrate compliance in accordance with point 21L.A.66;

(c) demonstrate that there are no unresolved issues from the physical inspection of the first article of that product in the final changed configuration carried out by the Agency in accordance with point 21L.A.66(e)(3).

AMC1 21L.A.68 Requirements for the approval of a major change to a type certificate

ED Decision 2023/013/R

(a) For major changes approved by EASA, the applicant should use all the AMC and GM to point 21L.A.25.

(b) For major changes approved by the design organisation approval (DOA) holder on the basis of its privileges under point 21.A.263(c)(8) of Annex I (Part 21), the process described in AMC No 2 to 21.A.263(c)(5), (8) and (9) applies.

AMC1 21L.A.68(c) Requirements for the approval of a major change to a type certificate

ED Decision 2023/013/R

For the demonstration by the applicant that there are no unresolved issues, see AMC1 21L.A.27(d).

21L.A.69 Approval of a change to a type certificate under a privilege

Regulation (EU) 2022/1358

(a) The approval of a change to a type certificate that it has designed may be issued by an approved design organisation without an application according to point 21L.A.65 in accordance with the scope of its privileges provided for in points (2) and (8) of point 21.A.263(c) of Annex I (Part 21) instead of the Agency, as recorded in the terms of approval.

(b) When issuing an approval of a change to type certificate in accordance with point (a), the design organisation shall:

1. ensure that all the substantiation data and justifications are available;

2. ensure that the compliance of the change with the type-certification basis and the applicable environmental protection requirements according to point (a)(1) of point 21L.A.67 or point (a) of point 21L.A.68 has been demonstrated and declared in accordance with point 21L.A.66;

3. confirm that it has not found:

(i) any non-compliances with the type-certification basis or, where applicable, with the applicable environmental protection requirements, or with the certification specifications chosen;

(ii) any feature or characteristic of the change that may make the changed product unsafe or environmentally incompatible for the uses for which certification is requested;

4. limit the approval of a change to a type certificate to the specific configuration(s) in the type certificate to which the change relates.

21L.A.70 Obligations for minor changes to a type certificate

Regulation (EU) 2022/1358

The holder of an approval of a minor change to a type certificate shall ensure that the obligations for holders of minor change approvals of Subpart A of this Annex are undertaken.