(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.