Staff Instruction (SI) No. 521-009

Division IX – Service Difficulty Reporting

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Issuing Office: Standards Document No.: SI 521-009
File Classification No.: Z 5000-32 U Issue No.: 01
RDIMS No.: 5612331-V27 Effective Date: 2011-09-07


1.1  Purpose

  1. The purpose of this Staff Instruction (SI) is to provide procedural guidelines for the handling, processing, investigating and closure of Service Difficulty Reports (SDRs) in accordance with Division VIII and IX of Subpart 521 of the Canadian Aviation Regulations (CARs). This SI should be used in conjunction with Advisory Circular (AC) 521-009.

1.2  Applicability

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

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. Part V Subpart 21 of the Canadian Aviation Regulations (CARs) – Approval of the Type Design or a Change to the Type Design of an Aeronautical Product;

    2. Subpart 101 of the CARs – Interpretation;

    3. Subpart 406 of the CARs – Flight Training Units;

    4. Subpart 561 of the CARs – Manufacture of Aeronautical Products;

    5. Subpart 573 of the CARs – Approved Maintenance Organizations;

    6. Subpart 604 of the CARs – Private Operators Passenger Transportation;

    7. Subpart 705 of the CARs – Airline Operators;

    8. Annex 8 to the Convention on International Civil Aviation;

    9. Maintenance and Manufacturing Staff Instruction (MSI) 50 – Instruction for Follow-Up Activity Regarding Suspected Unapproved Part Report,

    10. Advisory Circular (AC) 521-009 – Service Difficulty Reporting; 

    11. Transport Canada form number 24-0038, Version 0712-02 – Service Difficulty Report.

2.2  Cancelled Documents

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

    1. Aircraft Certification Staff Instruction (ACSI) 44 Issue 03, Service Difficulty Reporting Program.

  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. Approved Manual: includes a Maintenance Control Manual (MCM), Maintenance Policy Manual (MPM), Quality Control Manual (QCM) or similar TCCA approved or accepted manual for the purpose of this SI.

    2. Reportable Service Difficulty: a service difficulty that affects or that, if not corrected, is likely to affect the safety of an aircraft, its occupants or any other person (Section 101.01 of the CAR).

    3. Service Difficulty: a failure or malfunction of, or defect in, an aeronautical product.


3.1  Objective of the Service Difficulty Reporting Program

  1. The objective of the service difficulty reporting program is to achieve prompt and appropriate correction of conditions adversely affecting the continued airworthiness and safety of aeronautical products by:

    1. Collecting service difficulty reports (SDRs);

    2. Consolidating the SDR data into a common database;

    3. Analyzing the data to determine adverse trends;

    4. Investigating and if required developing corrective action; and

    5. Disseminating information to the aviation community.

  2. TCCA encourages secure and uninhibited reporting of service difficulties affecting aviation safety. Where no bad faith is apparent, TCCA will not prosecute or enforce proceedings regarding unintended or inadvertent regulatory infringements reported under the service difficulty report program as per AC 521-009.

3.2  The Service Difficulty Reporting Program

  1. The Service Difficulty Reporting Program is comprised of:

    1. Mandatory reporting: is applicable to the following organizations or individuals who are to submit each occurrence of a service difficulty on a “one SDR per event” basis:

      1. Flight Training Units—Section 406.11 of the CARs;

      2. Design Approval Holders—Subpart 521 of the CARs;

      3. Manufacturers of Aeronautical Products—Section 561.03 of the CARs;

      4. Approved Maintenance Organizations—Section 573.02 of the CARs;

      5. Private Operators–Passenger Transportation—Section 604.04 of the CARs; and

      6. Air Operators (Commercial Air Service including Aerial Work, Air Taxi, and Commuter—Section 705.07 of the CARs.

    2. Voluntary reporting: is applicable to members of the general aviation community, aircraft maintenance engineers (AMEs) and to those otherwise not specified under the mandatory requirements.

3.3  Web Service Difficulty Reporting System

  1. The TCCA SDR system is on the Internet as the Web Service Difficulty Reporting System (WSDRS) and consists of:

    1. A User Registration module;

    2. A User Inbox;

    3. An E-mail notification system; and

    4. An electronic SDR on-line submission facility.

  2. The WSDRS uses information captured from the National Aviation Company Information System (NACIS) to link the appropriate Principal Maintenance/Manufacturing Inspector (PMI) or Transport Canada Centre (TCC) office to the SDR submitters. NACIS is kept up to date to reflect current PMI assignments to avoid the re-direction of e-mails. SDRs submitted electronically via WSDRS are routed to the:

    1. Appropriate PMI’s Inbox to avoid any confusion with an Outlook or other mail program Inbox; or

    2. Nearest TCC superintendent for review, for those SDRs that do not have an associated PMI.

  3. An email is sent to the TCC superintendent or PMI, as applicable, notifying them of the SDR in their WSDRS Inbox.

  4. Please refer to AC 521-009—Service Difficulty Reporting for more information on submissions or assistance in the determination of a reportable occurrence.

3.4  Suspected Unapproved Parts

  1. Subpart 521 of the CARs, does not specify the reporting of suspected unapproved parts (SUPs), however it is still a requirement under Standard 571. Notification of SUPs to TCCA may still be made through use of the WSDRS.  When reports are submitted, the Continuing Airworthiness Division of National Aircraft Certification (NAC) will forward the information to the Standards Branch, Technical Programs division for further action in accordance with Maintenance and Manufacturing Staff Instruction (MSI) 50.


  1. The purpose of the service difficulty reporting program is to collect, analyze, record and disseminate data concerning reportable service difficulties which have resulted in, or may potentially result in, a safety hazard to an aircraft or its occupants. It is intended to use the reported information in support of regulatory activities to improve the level of aviation safety.  The service difficulty reporting program is TCCA’s primary tool to collect in-service data required to effectively carry out continuing airworthiness type design oversight responsibilities.

  2. Accordingly, TCCA will:

    1. Assess each report for airworthiness safety implications, both in itself and in relation to previous similar reports;

    2. Use a risk assessment process to determine whether mandatory corrective action is required;

    3. Use the data collected on a national basis to identify service difficulty trends not apparent regionally or to individual operators;

    4. Issue specific advice or instructions to particular sections of the aviation community;

    5. Take action in the form of:

      1. Directives which result in amendments to maintenance schedules, maintenance instructions and maintenance manuals;

      2. Advisory material to disseminate information and recommendations to the affected aviation industry and other bodies; and

    6. Ensure information reported is made available to the design approval document holder as recommended by Section of Annex 8 to the Convention on International Civil Aviation.

  3. TCCA's primary objective is to provide a secure, free and uninhibited reporting of service difficulties affecting aviation safety. The overall objective of the service difficulty report program is to use the reported information to improve the level of aviation safety and not to assign fault or apportion blame.

  4. It is fundamental to the purpose of the service difficulty reporting program that the substance of reports be disseminated when necessary in the interest of aviation safety. TCCA, however, commits itself to not publicly disclosing the name of the person or organization submitting a report, or of a person cited in the report. Information regarding the individual or organization submitting the SDR will be available to the design approval document holder to facilitate thorough investigation and resolution of safety issues.

  5. Specific subsections within the CARs specify those persons and organizations required to report the occurrence of service difficulties (see section 3.2 of this document). These persons and organizations are required to include in their maintenance control manual, quality control manual or equivalent manual, as applicable, the procedures used to report service difficulties.

  6. It is anticipated that operators submit the majority of reports because they, in most cases, will discover the service difficulty during the course of normal operations. To prevent duplication of reporting by manufacturers and maintenance organizations, operators should identify all items that have been reported as the subject of an SDR to the design approval document holder. This may be accomplished by attaching a copy of the SDR to the item, or annotating the documentation accompanying the item with the Service Difficulty Report form control number, or by any other convenient means. Approved Maintenance Organizations (AMO) will in the course of aeronautical product overhaul and repair work, discover service difficulties. In relation to the discovery of service difficulties in the course of overhaul or repair work, the responsibility for reporting may fall on the AMO. It is recognized that especially for components and appliances, it may be difficult for the AMO to assess whether a service difficulty would affect the safety of the aircraft as a whole, and may be impossible for this entity to complete some parts of the Service Difficulty Report form.

  7. When an AMO is in doubt about the applicability of the reporting requirements, (e.g. discovery of a service difficulty in a component or appliance which cannot be associated with a particular aircraft, or even a type of aircraft) it should submit as complete a report as possible to ensure that it has complied with the requirements of Division IX of Subpart 521 of the CARs and that the safety issue is reported.

  8. TCCA will transmit, via the WSDRS application, all SDRs received, which meet the reporting requirements of Division IX of Subpart 521 of the CARs to the respective design approval document holder. When an SDR is forwarded to the design approval document holder, an accompanying e-mail is forwarded. Transport Canada provides access to reportable service difficulty information, which has been forwarded to the design approval document holder, to the foreign airworthiness authority having jurisdiction over the type design of a foreign aeronautical product.


5.1  General

  1. The success of the Service Difficulty Reporting program (in identifying unsafe conditions, trends and where necessary developing corrective action) is dependant on the quality (accuracy and completeness) and that all reportable service difficulties are reported to the program. All TCCA Safety Inspectors and other personnel are to:

    1. Submit SDRs on any matter affecting airworthiness or safety that comes to their attention and that may not otherwise be reported; and

    2. Encourage all members of the aviation community to use the WSDRS by promoting the service difficulty reporting program at events such as AME symposia, trade shows, educational seminars, and company visits.

  2. All information sent via the WSDRS status update function is treated as public information unless otherwise indicated. In cases where information in an SDR is sensitive, a recommendation to withhold sensitive information from public view via e-mail or within the body of the status update text is sent to NAC. The Continuing Airworthiness, Corrective Action Technical Inspector (CATI) at NAC is to tag the status update as sensitive. Sensitive information that has been removed from the problem description and added to the supplemental text of the SDR shall not revealed to anyone other than the SDR submitter, the PMI, NAC and the design approval document holder.

5.2  Transport Canada Civil Aviation Enterprise Manager / Principal Maintenance/Manufacturing Inspector Responsibilities

  1. Regional Procedures for the service difficulty reporting program are detailed in Section 10 of this SI.

  2. The TCCA Enterprise Manager/PMI is accountable for ensuring compliance with the service difficulty reporting requirements:

    1. Organizations that are required by regulation to submit SDRs; where a reportable service difficulty is identified and no SDR is forthcoming, enforcement action is pursued.

    2. Where the submitter is not required to report a reportable service difficulty:

      1. Encourage the submission of an SDR, or

      2. Complete and submit an SDR with the available data in the case where a safety service difficulty exists and an SDR is not forthcoming;

    3. Report program issues to the Manager, Corrective Action, In-Service Investigations.

  3. Acknowledgement and follow-up of SDRs submitted under their area of jurisdiction.

  4. Monitoring of the Civil Aviation Daily Occurrence Report System (CADORS) for reported incidents that may be reported as an SDR.

5.3  National Aircraft Certification Responsibilities

  1. The NAC SDR processing procedure is contained in Section 11 of this SI.

  2. The Chief, Continuing Airworthiness, NAC, is accountable for the delivery of the service difficulty reporting program.

  3. NAC is responsible for:

    1. The overall management and administration of the service difficulty reporting program and its components as follows:

      1. SDR data management, including the assignment of SDR control numbers.

      2. Editing and updating of the SDR form and the WSDRS application and any other tools developed to promote support or administer the program to reflect the current data element requirements; and

      3. Amending the input into the service difficulty reporting program as per Division IX of Subpart 521 of the CARs, staff instructions, user manuals, etc.

      4. Maintaining the user library to reflect current users and their respective access levels (user class);

      5. Entering and reviewing SDR data in a timely manner;

      6. Providing safety intelligence from the SDR data by means of data analysis and trend monitoring; and

      7. Providing system training for regional and NAC personnel and industry.

    2. Specific program outputs such as:

      1. Preparing and issuing the necessary corrective action documents i.e. Airworthiness Directives, Civil Aviation Safety Alerts (previously Service Difficulty Alerts and Service Difficulty Advisories) or other published material as necessary;

      2. Co-ordinating service difficulty investigations; and

      3. Providing SDR project tracking and status updates.

    3. The administration of the service difficulty reporting program by:

      1. Providing co-ordination for lab analyses such as Lab Tests or Non-Destructive Testing (NDT) before a part is sent to a testing facility where necessary;

      2. Ensuring international liaison, which may include harmonization of the service difficulty reporting program and its data elements with other Civil Aviation Authorities’ (CAAs) systems.

      3. Ensuring that design approval document holders comply with the SDR reporting requirements as laid out in sections 521.353, 521.354 and 521.355 of the CARs.

5.4  Standards Branch Responsibilities

  1. Design the civil aviation program activities;

  2. Framework required for the implementation of the service difficulty reporting program.

    1. Developing the regulations to support the SDR reporting system.

    2. Developing the policy, procedures and guidance material setting out the process for the SDR reporting system.

  3. Ensure compliance with the SDR requirements of Annex 8 to the Convention of International Civil Aviation.


  1. Guidelines for incorporating mandatory reporting requirements into the organization’s approved manuals are contained in AC 521-009.

  2. Procedures are incorporated into an organization’s oversight plan to ensure they are submitting SDRs as per the procedures described in their approved manual and as required by Division IX of Subpart 521 of the CARs.


  1. The SDR form is maintained by NAC. The Regional Office is responsible for stocking, coordinating and distributing the SDR form to their TCCs.

  2. Blank electronic SDR forms are available from the TCCA Internet site at: The SDR form can be downloaded or completed online, then printed and faxed or mailed via regular mail to TCCA using the information shown on the Internet site above. Electronic submissions are made via WSDRS after an account has been set up using the registration module.

  3. Organizations may use alternate means to submit SDR information as per Division IX of Subpart 521 of the CARs provided they are:

    1. Pre-approved by the Continuing Airworthiness Division, NAC, and

    2. Recorded in the organization’s approved manual.


  1. TCCA and the Transportation Safety Board (TSB) are two governmental entities that have independent reporting requirements. For more information see AC 521-009.


  1. Supplementary information such as unit teardown/disassembly or lab reports related to a previously submitted report may be added to the SDR. To ensure that the supplementary information is properly filed, it is:

    1. Sent to NAC with the original SDR control number referenced; or

    2. By using the status update field on WSDRS. For more information on this procedure, please see the help guide on the WSDRS Internet site at: Web Service Difficulty Reporting System

  2. Control numbers are:

    1. Provided to PMIs and SDR submitters upon electronic submission on the WSDRS; and

    2. On the SDR copy that is returned to the respective TCC for forwarding to the submitter.

  3. Investigating a report often requires the expertise of various disciplines within TCCA. For example:

    1. An inspector may request information, advice or recommendations from the subject matter expert regarding a report; and 

    2. The subject matter expert is required to support the investigation.

  4. All information on which the disposition of the service difficulty is based is documented in the Continuing Airworthiness Web Information System/Web Service Difficulty Reporting System (CAWIS/WSDRS).

  5. The procedures in this SI are the minimum requirement to ensure that each SDR is adequately processed. Further information concerning a specific occurrence or service difficulty may be needed.


  1. The following outlines how the regions receive and process SDRs.

    1. All PMIs are to register on the WSDRS by following the initial log on procedures and creating an account to access their WSDRS Inbox. Please note that the NACIS database must be kept current as it is the source from which WSDRS obtains the PMI and operator information to provide the e-mail notifications of SDRs received via the Internet.

    2. Paper SDRs that are received by the Continuing Airworthiness Division at NAC will be scanned into PDF format after entry in WSDRS and provided to the appropriate Region so that they may provide confirmation to the SDR submitter that the SDR has been received.

    3. Any SDR submitted to the TCC office for onward submission must be forwarded to the Continuing Airworthiness Division in the NAC within one (1) working day. SDR submissions through the Regional or TCC office are discouraged, as the reports can be sent directly to the NAC using the self-addressed envelopes provided.

    4. The PMIs are the Office of Primary Interest (OPI) for investigations involving their operators. For the follow-up of an SDR  that may be under investigation by Headquarters (HQ), the office of technical interest will:

      1. Carry out or assist with an investigation where requested by NAC;

      2. Contact the originator of the SDR if required to request additional details, obtain photographs, request teardown/disassembly reports, or obtain parts, where applicable;

      3. Determine if parts are to be submitted to the TSB for analysis, and seek appropriate funding. If funding is sought from NAC, prior approval must be received from the Continuing Airworthiness Division before parts are forwarded to any laboratory;

      4. Forward additional information and recommendations to the SDR Program Manager, NAC and update the WSDRS status field of the SDR in question; and

      5. Follow up with the originator of the SDR if required and provide a status update regarding any action taken by the Continuing Airworthiness Division in NAC or the OPI of the regional investigation.

    5. For mailed in hard copy SDRs, using form 24-0038, an acknowledgement letter must be sent to the originator within the TCC or region’s jurisdiction using the supplied standard acknowledgement letter (RDIMS 5839140) along with the SDR hard copy provided by HQ. Electronically submitted SDRs have an automated process that acknowledges and provides confirmation that the SDR has been received in HQ. Therefore, no acknowledgement letter action is required for SDRs submitted electronically through the WSDRS.

    6. The WSDRS is designed to replace any tracking systems currently in place in the regions. All other copies of SDRs need not be retained upon transmission of the acknowledgement letter to the submitter.


  1. The following outlines how NAC receives and processes SDRs.

    1. An SDR is sent to NAC via:

      1. Direct mail (paper);

      2. Fax (paper); or

      3. The WSDRS.

    2. For paper copy SDRs:

      1. The corrective action assistant records the SDR’s information in CAWIS/WSDRS.  The WSDRS application assigns a Control Number (SDR number) and creates new electronic preliminary status ‘P’ in the SDR database;

      2. The corrective action assistant attaches a PDF copy of the SDR to the electronic version and forwards the encrypted PDF copy to the respective TCC office or region within thirty (30) days; and

      3. The SDR is assigned to the appropriate CATI, as per the responsibility matrix on the Continuing Airworthiness Division Internet site at:  Refer to (d) below for CATI’s actions.

    3. For electronic submissions of SDRs via WSDRS:

      1. The system assigns an SDR control number and status code ‘P‘ (preliminary status) automatically;

      2. A confirmation that the SDR has been received is sent automatically to the submitter;

      3. An automatic e-mail notification is sent to the PMI or appropriate TCC Superintendent and NAC; and

      4. The SDR is automatically assigned to the appropriate CATI.

    4. The CATI actions the SDR by:

      1. Evaluating the SDR and, where needed, gathering additional information from the submitter;

      2. Gathering additional information from the design approval document holder when their involvement is required;

      3. Initiating the trend review to determine the impact and to review service history where deemed appropriate;

      4. Changing SDR HQ status from ‘P’ to “R” – Revised; and

      5. Determining the next appropriate action, (Feed-Back article, Civil Aviation Safety Alerts, data only) or to carry out a more in-depth investigation of the problem.

    5. If further investigation is required:

      1. The CATI carries out an in-depth investigation of the SDR and a project is initiated and logged on the Project Tracking System (PTS) in CAWIS;

      2. The SDR is flagged with a project indication, which notifies the PMI of the investigation via the WSDRS user Inbox; and

      3. The TSB lab, Civil Aviation Safety Inspectors, outside departments or others within the Safety and Security Directorate, the manufacturer or foreign authorities may be consulted;

    6. A decision is made on the final disposition of the SDR, appropriate corrective action is taken, and the SDR is updated with the latest status information.

    7. If a project is ongoing on the SDR, status updates are provided in the Status memo field. Notification of the updates is automatically forwarded by e-mail to personnel with a direct interest in the SDR in question.

    8. If a recommendation for Airworthiness Directive action is made, information is prepared and supporting documentation is forwarded to the appropriate corrective action unit in NAC for their disposition.

    9. If other types of corrective action are warranted, the CATI will update the CAWIS PTS and prepare the material for publication.

    10. Publication material is routed to the appropriate publications unit of NAC for dissemination to the public.


Suggestions for amendment to this document are invited, and should be submitted via the following e-mail address: Attn: Chief, Aircraft Certification Standards (AARTC)

[original signed by Jean-François Mathieu for]

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


Continuing Airworthiness - Service Difficulty Reporting Process

Continuing Airworthiness - Service Difficulty Reporting Process

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