---
title: "Appendix B to GM 21L.A.63 Classification of changes to a type certificate — Annex Ib, Initial Airworthiness · Avioverse"
description: "The following tables provide examples of ‘substantial’ changes."
url: "https://avioverse.aero/regulations/easa/initial-airworthiness/annex-ib/section-a-technical-requirements/appendix-b-to-gm-21l-a-63"
---

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

Annex Ib · Regulation (EU) No 748/2012 · EAR revision 27 Nov 2025

Appendix Appendix

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

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)

| Example | Description of change                                                         | Notes                                                                                                                                                             |
| ------- | ----------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 1.      | Change to wing location (tandem, forward, canard, high/low).                  | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |
| 2.      | Fixed wing to tilt wing.                                                      | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |
| 3.      | A change to the number of engines.                                            | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |
| 4.      | Replacement of piston or turboprop engines with turbojet or turbofan engines. | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |
| 5.      | Change to engine configuration (tractor/pusher).                              | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |
| 6.      | Change from an all-metal to all-composite aeroplane.                          | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |

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)

| Example | Description of change                                                                                     | Notes                                                                                                                                                             |
| ------- | --------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 1.      | Change to the number and/or configuration of rotors (e.g. main and tail rotor system to two main rotors). | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |
| 2.      | Change from an all-metal rotorcraft to all-composite rotorcraft.                                          | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |

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)

| Example | Description of change           | Notes                                                                                                                                                             |
| ------- | ------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 1.      | Change to the number of blades. | Proposed change to the design is so extensive that a substantially complete investigation of compliance with the applicable type-certification basis is required. |

APPENDIX · Appendix B to GM 21L.A.63 — Regulation (EU) No 748/2012 · ED Decision 2023/013/R · Initial Airworthiness Easy Access Rules · EAR revision 27 Nov 2025

[All rules in SECTION A - TECHNICAL REQUIREMENTS](https://avioverse.aero/regulations/easa/initial-airworthiness/annex-ib/section-a-technical-requirements)

Consolidated from the EASA Easy Access Rules (revision 27 Nov 2025, extracted 13 Oct 2026) for convenience. Not the official publication — verify against the Official Journal of the European Union and the EASA publications before operational use.