1. INTRODUCTION.

1.1 REFERENCE DOCUMENTS.

Reference	Title
[1] Point 21.A.101	Designation of applicable certification specifications and environmental protection requirements
[2] GM 21.A.101-1B	Establishing the Certification Basis of Changed Aeronautical Products
[3] XXXX	Application letter
[4] Type Certificate YYYY	Product type-certification basis
[5] Document ZZZZ	Certification plan

<The above-referenced documents are examples. Each applicant should reference documents appropriate to their products and procedures.>

1.2 ACRONYMS.

Acronym	Meaning
AFM	Aircraft Flight Manual
AMC	Acceptable Means of Compliance
CRI	Certification Review Item
ELOS	Equivalent Level of Safety
ESF	Equivalent Safety Finding
GM	Guidance Material
MOC	Means of Compliance
SC	Special Condition
TC	Type Certificate

<This section constitutes a representative list of acronyms. Each applicant should provide an acronym list appropriate for their product and document.>

1.3 PURPOSE OF THE DOCUMENT.

The purpose of this document is to propose the certification basis applicable to [Product Design Change] in accordance with point 21.A.101.

<Note that this optional document is intended to be used for changes to type-certified products for which the change or a portion of the change is significant at the product level pursuant to 21.A.101. Not significant changes being accomplished concurrently with significant changes(s) would also be identified in this document.>

2. DESIGN DEFINITION.

2.1 BASELINE PRODUCT.

The type design to be changed, which is also known as the ‘baseline product,’ is the Model Series____(this should be a specific product configuration, such as a specific serial number or line number).

The reference product certification basis is TCDS No. [XXXX], issued on [DATE].

2.2 DESIGN CHANGE AND BASELINE PRODUCT COMPARISON SUMMARY.

<Example table where the product is an aeroplane. This is a representative set of data that may be provided by the applicant.>

Specification	Model Series X	Model Series Y
Max Taxi Weight — MTW (lb)	A1	A2
Max Take-off Weight — MTOW (lb)	B1	B2
Max Landing Weight — MLW (lb)	C1	C2
Max Zero Fuel Weight — MZFW (lb)	D1	D2
Max Length (ft, in)	E1	E2
Max Height (ft, in)	F1	F2
Wing Span (ft, in)	G1	G2
Horizontal Tail Span (ft, in)	H1	H2
Fuel Capacity (gal)	I1	I2
Total Cargo Volume (ft3)	J1	J2
Max Passenger Limit — one class seating (occupants)	K1	K2
Engine Types	L1 & M1	L2
Maximum Engine Thrust	T1	T2

2.3 DESCRIPTION OF DESIGN CHANGE, GROUPING AND CLASSIFICATION.

2.3.1 SIGNIFICANT CHANGE(S).

<Describe here the stand-alone change(s) and/or change grouping(s) that are part of the proposed changed product and are proposed as significant. Include with each stand-alone change or change grouping the relevant accumulated change(s) and the applicable physical and/or functional effects. Note, the description should be detailed enough to identify why the change or change grouping is proposed as significant.>

The following group of changes is proposed as significant based on [GM 21.A.101-1, Appendix A, ‘[Description of Change in Appendix A]] or [the general configuration is not retained, principles of construction are not retained, or assumptions for certification of the product to be changed do not remain valid].

Changes Related to [Title of Significant Change X]:

[Title of High-Level Change C1]

The areas of physical change are:

— [design change xx]

— [design change yy]

— [design change zz]

The areas unchanged but affected by the change are:

— [affected area aaa]

— [affected area bbb]

— [affected area ccc]

[Title of High-Level Change C2]…

2.3.2 UNRELATED NOT-SIGNIFICANT CHANGES.

<Describe here the not significant stand-alone changes or change groupings that are part of the modification but are unrelated to any of the significant changes described in paragraph 2.3.1.>

[Title of High-Level Change D1]. [Description].

<The description must be just detailed enough to serve its purpose, which is to identify why each of those changes is not significant and unrelated.>

[Title of High-Level Change D2]. [Description]…

3. IDENTIFICATION OF APPLICABLE CERTIFICATION STANDARDS.

3.1 PROPOSED CERTIFICATION BASIS.

Based on the effective application date, [date], under the provisions of 21.A.101, the applicable certification standards for the [Title of Design Change] are proposed as follows. The proposed certification basis includes exceptions to earlier amendments (reversions), deviations, special conditions, and equivalent (level of) safety findings.

3.1.1 Certification specifications effective at the date of application.

Applicable certification specifications in effect on the date of the application are:

<List the applicable parts and amendment levels here.>

Example for large aeroplanes:

A. Airworthiness:

—    CS-25,

— CS-AWO.

B. Operational Suitability Data:

— CS-CCD,

— CS-FCD,

— CS-MCSD (to be published),

— CS-MMEL,

— CS-SIMD.

C. Environmental Protection:

—    CS-34,

—    CS-36.

3.1.2 Point 21.A.101 exception rationale.

The completed rationale for each does not contribute materially to the level of safety (DCMLS) or impracticality exception is provided in this section.

Exception 1: …

Exception 2: …

3.1.3 Optional certification standards

Applicable certification specifications in effect on the date of the application are:

<List the applicable parts and amendment levels here.>

Example for large aeroplanes:

— CS 25.803, Emergency evacuation, Amendment 12,

— CS 25.1810, Emergency egress assisting means and escape routes, Amendment 17.

3.1.4 Design-related requirements from other aviation domains.

Applicable certification specifications in effect on the date of the application are:

<List the applicable parts and amendment levels here.>

Example for large aeroplanes:

— CS-ACNS Communications, Navigation and Surveillance

— Initial Issue, dated 17 December 2013, Subpart D Sections 2/3,

— CS-26.

3.1.5 Proposed Special Conditions.

Special Condition (or TBD)	Title	Effective Date (or TBD)

3.1.6 Equivalent Safety Findings.

ELOS Memo No (or TBD)	Title	Applicable Standard

3.1.7 Deviations.

Deviation No (or TBD)	Title	Applicable Standard	Date Issued (or TBD)

3.1.8 Elect to comply.

Elect to comply(or TBD)	Title	Applicable Standard	Date Issued (or TBD)

Proposed Certification Basis

The certification basis is a complete extract from the applicable FAA 14 CFR part [A] and it references the certification basis [B]. Column [C] identifies the amendment level for the specific requirement on the date of application. The changed product’s certification basis is proposed in last column [D]. References to FAR sections and amendments are kept.

Example for a Part 25 aeroplane:

[A] Requirement	Title (or subparagraph)	[B] Existing Certification Basis Amendment Level	[C] Amendment Level on Application Date	[D] Proposed Amendment for Changed Product	Applicable Area	Notes
25.25	Weight limits
		25-23	25-63	25-63	Product
25.33	Propeller speed and pitch limits
		N/A	25-72	N/A	—	Not applicable to Changed Product (Jet Aircraft)
25.1309(a)	Equipment, systems, and installations
		25-41	15-123	25-123	Changed and Affected Areas
		25-41	25-123	25-41	Exception — Not Affected	See example 1 in section 3.1.2
25.1703	Function and installation: EWIS
		N/A	25-124	N/A	Exception — Product	See example 2 in section 3.2.1