Staff Instruction (SI) No. 521-006

Repair Design Approvals

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Issuing Office: Civil Aviation Document
SI 521-006
File Classification No.: Z 5000-32 Issue No.: 01
RDIMS No.: 5612310-V27 Effective Date: 2012-03-16


1.1  Purpose

  1. The purpose of this Staff Instruction (SI) is to provide general information and basic procedures relating to:

    1. the review and approval of Canadian repairs to the type design of aeronautical products through the issuance of a repair design approval (RDA) as governed by Subpart 521 of the Canadian Aviation Regulations (CARs); and

    2. the original issue of Repair Design Approval (RDAs) and follow-on revisions.

  2. This document is to be used in conjunction with SI 521-004.

1.2  Applicability

  1. This document applies to all Transport Canada Civil Aviation (TCCA) employees and Ministerial Delegates. This information is also available to the aviation industry for information purposes.

  2. This SI does not apply to products approved by a Canadian Technical Standard Order (CAN-TSO) design approval.

1.3  Description of Changes

  1. Not Applicable.


2.1  Reference Documents

  1. It is intended that the following reference materials be used in conjunction with this document:

    1. Aeronautics Act (R.S., 1985, c. A-2);

    2. Part I, Subpart 4 of the Canadian Aviation Regulations (CARs)—Charges;

    3. Part V, Subpart 21 of the CARs—Approval of the Type Design or a Change to the Type Design of an Aeronautical Product;

    4. Staff Instruction (SI) 500-018,— Design Approval Document Transfers under CAR 521: Division VIII —Responsibilities of a Design Approval Document Holder;

    5. SI 521-004—Changes to the Type Design of an Aeronautical Product;

    6. Advisory Circular (AC) 521-002,—Type Certification Requirements of Aircraft, Engines and Propellers;

    7. AC 521-006,—Repair Design Approvals; and

    8. Notice of Proposed Amendment (NPA2010-021Approval of the Type Design or Change to the Type Design of an Aeronautical Product.

2.2  Cancelled Documents

  1. As of the effective date of this document, the following document is cancelled:

    1. SI 513-007, Issue 01, 2007-01-15Approval of Domestic Modification and Repair Designs.

  2. By default, it is understood that the publication of a new issue of a document automatically renders any earlier issues of the same document null and void.

2.3  Definitions

  1. The following definitions are used in this document:

    1. Aeronautical Product: an aircraft, aircraft engine, aircraft propeller or aircraft appliance or part, or a component part of any of those things, including any computer system and software (Ref. Aeronautics Act R and Section 521.01 of the CARs).

    2. Certification Basis: refers to the applicable standards as established in Section 521.157 of the CARs, as appropriate, including any special conditions—airworthiness (SCA), findings of equivalent level of safety, and exemptions applicable to the product to be certified.

    3. Conformity with the Certification Basis: demonstrating compliance with all of the applicable standards and requirements of the certification basis.

    4. Delegate: any person or class of persons authorized under the authority of Subsection 4.3(1) of the Aeronautics Act to perform functions on behalf of the Minister, subject to the requirements in Chapter 505 of the Airworthiness Manual (AWM).

    5. National Aeronautical Product Approval (NAPA) System: an automated system that provides staff in aircraft certification with the tools necessary to track the certification of aeronautical products and issue the design approval documents. This system also provides a database of the projects and supporting data for this certification.

    6. Repair: the rectification of deficiencies in an aeronautical product or the restoration of an aeronautical product to an airworthy condition (Subpart 101 of the CARs).

    7. Repair Design Approval (RDA): a document, including a repair design certificate issued before December 1, 2009 under Section 513.11 or 513.22 of the CARs, issued by the Minister to record the approval of:

      1. a repair design in respect of a repair to an aeronautical product identified in the document by a serial number; or

      2. a repair process in respect of a repair to an aeronautical product or any of its components, identified in the document by a serial number, by a part number or by some other identification unique to the component.

      (Ref: Subsection 101.01(1) of the CARs)
    8. Standards of Airworthiness: design requirements as defined in the AWM. For design changes, the standards of airworthiness may also be listed on the type certificate data sheet (TCDS).

    9. Type Design:

      1. the drawings and specifications, and a listing of those drawings and specifications that are necessary to define the design features of an aeronautical product in compliance with the standards applicable to the aeronautical product;

      2. the information on dimensions, materials and manufacturing processes that is necessary to define the structural strength of an aeronautical product;

      3. the approved sections of the aircraft flight manual, where required by the applicable standards of airworthiness;

      4. the airworthiness limitations section of the instructions for continued airworthiness specified in the applicable chapters of the AWM; and

      5. any other data necessary to allow, by comparison, the determination of the airworthiness and, where applicable, the environmental characteristics of later aeronautical products of the same type or model.

        (Ref: Subsection 101.01(1) of the CARs)


  1. With the implementation of Subpart 521 of the CARs new documents have been created to support the regulations. All guidance material such SIs, ACs and Policy Letters  that supported the previous CARs and Chapters 511, 513, 591 and 593 of the Airworthiness Manual (AWM) have been reviewed and the relevant material included in the 521 series ACs and SIs.

  2. This SI is organized to mirror Sections and Subsections of Subpart 521 of the CARs, Division VI so that it can be easily read in conjunction with Subpart 521 of the CARs.

  3. Although Subpart 521 of the CARs introduced a change in terminology in the English version from “compliance” to “conformity” this SI will be using “compliance” wherever possible to minimize confusion in this document.

    In December 2010, a Notice of Proposed Amendment (NPA) to Subpart 521 of the CARs (NPA 2010-021) was introduced to revert the terminology “conform” and “conformity” back to “comply” and “compliance.”


  1. The requirements that must be fulfilled to obtain an RDA as a result of a repair are defined in Division VI—Repair Design Approvals and Division IV—Changes to a Type Design within Subpart 521 of the CARs. This SI should be used in conjunction with SI 521-004.

  2. Sections 521.251 to 521.253 of the CARs define the requirements of an applicant for an RDA.  Sections 521.254 and 521.255 of Division VI and Sections 521.157 to 521.160 of Division IV establish the certification requirements as well as the requirements for demonstrating that the repair complies with all certification requirements. Sections 521.256 and 521.257 of Division VI and Section 521.161 of Division IV define the design approval issuance and subsequent revision requirements.


5.1  Application - Section 521.251

  1. This SI applies to applications for a Canadian RDA under Subpart 521 of the CARs, Division VI.

  2. Any Canadian individual or organization may apply for an RDA. Canadian design approval documents are not issued directly to foreign applicants. Refer to Subpart 521 of the CARs, Division XI for more information on foreign aeronautical products.

5.2  Eligibility Requirements - Section 521.252

  1. Section 521.252 of the CARs requires the applicant to have or have access to the required technical capabilities specific to the repair under consideration. An applicant could meet this requirement by:

    1. Having a level of knowledge and capability appropriate for the repair; or

    2. Showing that an arrangement exists for the applicant to have access to a level of knowledge and capability appropriate for the repair.

  2. For more detailed information on how the Minister determines technical capability, refer to AC 521-002.


6.1  Application for a Repair Design Approval - Section 521.253

  1. Applications for an RDA are processed in accordance with the procedures defined in SI 521-004.

  2. RDAs are not modifications to the type design but rather they restore the airworthiness of an aeronautical product to its approved type design.

  3. A single repair (as opposed to a process) RDA applies to one aeronautical product type on one type certificate and a single serial number, e.g. in the case of damage from an accident that affects the fuselage, landing gear and engine, one RDA can be issued for the fuselage and landing gear; however a separate RDA would be issued for the engine repair.

  4. A process RDA is a repair that is repeatable and can cover aeronautical products from multiple type certificates; e.g. repair to a wheel assembly that might be installed on different aircraft models.

  5. A process RDA should also be used when making repairs to rotable parts.

6.2  Establish Certification Basis – Section 21.254

  1. Establishment of the certification basis is to be conducted in accordance with Subsection 521.158(2) of the CARs).


  1. SI 521-004 provides information on establishing means of compliance and TCCA’s level of involvement .


8.1  Compliance with Certification Basis - Section 521.255

  1. Compliance demonstration with the certification basis is to be conducted in accordance with the procedures defined in SI 521-004 (Section 521.160 of the CARs).


9.1  Issuance of a Repair Design Approval - Section 521.256

  1. Issuance of an RDA is to be conducted in accordance with the procedures defined in SI 521-004 (Section 521.256 of the CARs) and the guidance provided in this section.

  2. A sample of a single repair RDA is provided in Appendix A and a process repair in Appendix B of this SI.

  3. The certificate format and numbering system for RDAs is as described in Appendix C of this SI.

  4. An RDA should be issued wherever possible by an appropriately authorized delegate, not by TCCA. This includes RDA projects where TCCA has some involvement such as making findings of compliance for design paragraphs not delegated. Delegate issued RDAs bear the suffix “/D”.

  5. A process checklist is provided in Appendix D of this SI.

  6. A transmittal letter template is provided in Appendix E of this SI.

  7. Additional guidance on the issuance of approvals is provided in SI 521-004.


10.1  Change to a Repair Design Approved in a Repair Design Approval - Section 521.257

  1. Revisions for the purpose of adding references to new or revised engineering data, or for incorporating other necessary changes or corrections, shall be annotated with a vertical bar adjacent to the right hand margin to indicate the changes on the certificate.

  2. TCCA Aircraft Certification personnel shall not reissue:

    1. Approvals originally issued by a delegate; or

    2. Approvals originally issued by another region, unless the associated project files have been transferred from the other region.

  3. When transferring the ownership of an aircraft, which is repaired in accordance with an RDA, the following options are available:

    1. The original holder will retain responsibilities; or

    2. Re-issue the RDA to the new aircraft owner who will take on the responsibilities of the holder, and accept the obligations of Subpart 521 of the CARs, Division VIII – Responsibilities of a Design Approval Document Holder.

  4. For certificate transfers, refer to Section 521.357 of the CARs and SI 500-018.


  1. It is not the intent that TCCA keep copies of the applicant’s supporting data after the approval is issued. The holder has retention obligations under Section 521.365 and 521.366 of the CARs.

  2. TCCA files will retain key compliance related information such as certification plans, issue papers and decision records as well as any data cited on the approval document such as flight manuals and supplements, maintenance manuals/Instructions for continued airworthiness (ICAs) and master document lists.

  3. After approval is issued, TCCA will upon request by the applicant, return paper copies of supporting data or otherwise shred or erase this data.


  1. Not applicable.


Suggestions for amendment to this document are invited, and should be submitted to:

Chief, Aircraft Certification Standards (AARTC) via the following e-mail address:

Original signed by

Jacqueline Booth
A/Director, Standards Branch
Civil Aviation
Transport Canada



Department of Transport

Repair Design Approval

This approval is issued to: 
123456 Canada Inc.
Acme Aerospace Ltd.
8876 Any Street
Anytown, Quebec
H1S 2B6

Number: Q-RA09-099
Issue No.: 1
Approval Date: May 23, 2009
Issue Date: May 23, 2009

Responsible Office:

Aircraft/Engine Type or Model:

Registration/Serial No.:

Canadian Type Certificate or Equivalent:

Description of Type Design Change:


Pioneer H400

C-ABCD – Serial # AA-341


Repair to Horizontal Stabilator Hinge Brackets -
P/N 124-448923-3 / -4

Installation/Operating Data,
Required Equipment and Limitations:

Horizontal Stabilator Hinge Brackets – P/N 124-448923-3/ -4 repair is to be performed in accordance with Transport Canada approved Acme Aerospace Ltd. Repair Engineering Order (REO) #AA-3030-AEO-1000, Revision 2 dated May 1, 2010 or later Transport Canada Approved Revision.

- End -


Conditions: This approval is only applicable to the type/model of aeronautical product specified therein. Prior to incorporating this repair, the installer shall establish that the interrelationship between this repair and any other modification(s) incorporated will not adversely affect the airworthiness of the modified product.

John Q. Rollins
For Minister of Transport

Canada wordmark



Department of Transport

Repair Design Approval

This approval is issued to: 
123456 Canada Inc.
Acme Aerospace Ltd.
8876 Any Street
Anytown, Quebec
H1S 2B6

Number: Q-RE11-023
Issue No.: 1
Approval Date: May 10, 2010
Issue Date: May 10, 2011

Responsible Office:

Aircraft/Engine Type or Model:

Registration/Serial No.:

Canadian Type Certificate or Equivalent:

Description of Type Design Change:


Pioneer H-400 Series

Process RDA


Repair Alignment Holes on Air Impingement Manifold

Installation/Operating Data,
Required Equipment and Limitations:

Repair will be done in accordance with Acme Aerospace Master Data List MDL # AA-0007-MDL, Revision 1, approved May 9, 2011 or later Transport Canada approved revision.

- End -


Conditions: This approval is only applicable to the type/model of aeronautical product specified therein. Prior to incorporating this repair, the installer shall establish that the interrelationship between this repair and any other modification(s) incorporated will not adversely affect the airworthiness of the modified product.

John Q. Rollins
For Minister of Transport

Canada wordmark



The following provides guidance with respect to the development of approvals. Aircraft Certification personnel will use the NAPA system to generate the appropriate approval certificates.

Sections of the Certificate Description
This approval is issued to: The name and address of the approval holder as identified on the application form.

The sharing of design responsibilities is not acceptable, thus the approval must be issued in the name of one holder only.
Number: As generated by the NAPA system.  Number will be unique and reflect the region of issue, type of approval, year of issue, and the next available sequential number.
Issue No.: As generated by NAPA System.  Next sequential number updated each time the approval is re-issued.
Approval Date: The date that the original design change is approved.  The original approval date does not change when a certificate is revised.
Issue Date: The date of issue of the approval, which must be equivalent to, or later than the approval date.
Responsible Office: Atlantic, Quebec, Ontario, Prairie & Northern, Pacific or Headquarters, as applicable.
Aircraft/Engine Type or Model: The specified type (or types), and model designations, as referenced on the applicable type certificate(s).

If it is a component repair on multiple aircraft types (process RDAs), use the appropriate part numbers.
Registration*/Serial No.:

*Since registration numbers can change frequently it is recommended that they not be added to the RDA.
Appropriate serial number for an RDA.

”Process RDA” if it is a process RDA.

If the aircraft is not Canadian-registered, the installer must ensure that the repair is acceptable to the Civil Aviation Authority that registered the aircraft.
Canadian Type Certificate or Equivalent: Canadian TCDS reference or accepted foreign TCDS reference if no Canadian one exists.
Description of Type Design Change: The title of the repair.  This should convey the intent/affect/nature of the repair, not a marketing trade name. It also should be somewhat specific rather than general. Example – “Intercostal Repair at Station xxx” as opposed to “Structural Repair”.
Installation / Operating Data, Required Equipment and Limitations: To read:

Repair must be in accordance with (name of document holder, master document list/document number, revision level), TCCA approved (date of approval) *

Also include, where applicable:

Maintenance must be in accordance with TCCA accepted (name of holder) Instructions for Continued Airworthiness, (revision level), (date) **

(References to additional installation data, maintenance manual supplement, operating limitations and placards).
Separate ‘Required Equipment:’ and ‘Limitations:’ subheadings may be added when deemed appropriate.


*The phrase “or later TCCA approved revision” may be included.
** The phrase “or later TCCA accepted revision” may be included.


The TCCA approved or accepted date shall be used when applicable.  Otherwise, the document’s revision-specific date shall be used.
Certification Basis Not required to be cited on the RDA certificate since the basis of certification is specified as that of the TCDS for the aeronautical product as determined by Subsection 521.158(2) of the CARs.
End of text: If continuation sheets are required, add the note ‘– See Continuation Sheet –’.
The end of the text shall be  marked: – End –
Signature/Seal: The individual holding signing authority shall include their name and signature on a sealed certificate, on behalf of the Minister of Transport.

TCCA Project Engineers should only use their names and not include professional designations or degrees held.

If the certificate is issued by a delegate, their delegate number shall follow their name:

J. Smith, DAR 999
J. Smith, DAO 99-O-01, DE 1
J. Smith, AEO 99-Q-01, DE 1

The person signing the certificate must have verified that compliance has been shown for all areas on the compliance program for which the approval is issued.


NAPA automatically assigns numbers for design approval documents.


TCCA Issued Aeroplane RDA:

Text description
TCCA Issued Aeroplane RDA

Delegate Re-Issued Helicopter RDA:

Text description
Delegate Re-Issued Helicopter RDA:

The number assigned to an RDA is comprised of the following elements:

(1) An upper case “R” for RDA.

(2) For RDAs, a Regional or HQ identifier is used as follows:

A Atlantic O Ontario
C Prairie & Northern P Pacific
H HQ Q Québec

(3) One or two upper-case letters indicating the category of aeronautical product that is eligible for the modification or repair, as follows:

A Airplane F Float
AP Appliance G Glider
B Balloon H Helicopter
E Engine P Propeller

(4) Two numerical digits corresponding to the year of the approval date.

(5) A hyphen and sequential number, automatically generated by NAPA.

(6) For a Delegate issued certificate, the sequential number is suffixed with “/D”.

(7) The appropriate issue number, beginning with 1. (Non-numeric designations such as “N/C”, “IR”, or “no revision” are not acceptable).


The following checklist will aid the quality control of the approval certificate issued:

Item Details Yes No N/A
1 Is the holder legal name listed correctly?
2 Is the issue number correct? (i.e. if the last issue was a 2, then this would be a 3).
3 Are the approval and issue dates correct?
E.g. For Issue 1, the Issue Date and Approval Date must match.
4 Are the aeronautical product types or models listed correctly?
5 Is the product serial number correct if the certificate is serial number specific?
6 Are the type certificates listed appropriate to the models listed?
7 Is the title of the repair reflective of the restoration at a fundamental level?
8 Are the documents used for the repair listed accurately?
9 Are the dates of the documents listed on the certificates the same as the approval/acceptance dates on the actual referenced documents?
10 Has the certificate been signed?
11 Has your delegation number been identified?
E.g. DAO # and DE #
12 Has the stamp been embossed?


{Office Address}
{City, Province, Postal Code}    

{Your file no.}


{Our file no.}
{Our file no. 2}

{Company Address}

SUBJECT:   {Approval Number}

This {Approval Number} is issued in response to your application. Included with the {Approval Number} are the documents bearing original Transport Canada signatures.

The transfer of this {Approval Number} in the name of another person requires the prior approval from the Minister in accordance with Section 521.357 of the Canadian Aviation Regulations (CARs).

Embodiment of repairs requiring certification of detail part fabrication and installation, in accordance with approved data identified on the certificate, is considered to be a maintenance activity and the requirements of Subsection 571.06(4) of the CARs will apply.

A Canadian Holder is required to fulfill the responsibilities of a Design Approval Document Holder in accordance with Subpart 521 of the CARs, Division VIII, including the reporting of any service difficulties experienced with their product. Therefore, should you become aware of any defect, malfunction or failure resulting from the repair; it is your responsibility to submit a Service Difficulty Report to Transport Canada.

Yours truly,

Senior Engineer, Aircraft Certification


Transport Canada documents or intranet pages mentioned in this document are available upon request.

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