November 28, 2022
Aircraft Maintenance Engineer (AME) Licence Holders and Aircraft Owners
Interim Changes to Small Private Aircraft Maintenance Schedule Tolerance and Deviation Requests Due to the COVID-19 Pandemic
This notice is to provide interim policy changes and information on small private aircraft maintenance schedule tolerance and deviation due to COVID-19.
It includes how an appropriately rated and valid AME licence holder (known herein as AME) can apply a tolerance to a task required by a maintenance schedule in accordance with paragraph 625.86(8)(b) of Standard (STD) 625, or as an alternative, on how an aircraft owner may obtain an authorization to deviate from their maintenance schedule from Transport Canada Civil Aviation (TCCA) in accordance with subsection 605.86(3) of the Canadian Aviation Regulations (CARs).
This notice applies to AMEs and owners of small privately operated type certified piston engine aircraft (aeroplanes and helicopters) that have been issued a Certificate of Airworthiness pursuant to section 507.02 of the CARs (known herein as small private aircraft), maintained in accordance with a maintenance schedule conforming to STD 625 Appendix B and C as required by section 605.86 of the CARs.
This notice is valid until June 30, 2023 unless amended or cancelled by TCCA, or when a new Advisory Circular (AC) on the subject is published.
Tolerance to a task required by a maintenance schedule by an AME:
A tolerance may be applied by an AME to an interval of a task required by a small private aircraft maintenance schedule conforming to STD 625 Appendix B and C in accordance in subsection 625.86(8), provided the task is not overdue based on its last completion.
Prior approval for use of a tolerance by TCCA is not required. However, a tolerance cannot be applied to maintenance schedule task that is overdue.
Furthermore, in no circumstance can a tolerance be applied to tasks mandated by airworthiness limitations or airworthiness directives, as either a regulator exemption or an alternate means of compliance to these types of tasks will require formal approval from the National Aircraft Certification Branch, TCCA.
The following key elements and acceptable practices are to be applied as part of the tolerance process:
- Role and responsibilities;
- Acceptable tolerance limits;
- Aircraft inspection;
- Selection of the tolerance; and
- Technical record and maintenance release.
1. Roles and responsibilities:
An aircraft owner is responsible for the maintenance of their aircraft including that it is accomplished on time. This includes providing access to the aircraft and its technical records to the AME.
An AME is responsible for the performance of the maintenance requested by the owner, utilizing the applicable standards of airworthiness and the signing of a maintenance release. An AME may or may not be employed by an Approved Maintenance Organization (AMO). The AME needs to be appropriately rated for the work being requested and have the appropriate experience and skill on the aircraft make and model.
When a tolerance may be required, the aircraft owner needs to request the services of an AME far enough in advance in order to have their aircraft inspected to ensure that it is in satisfactory condition to determine whether a tolerance can be applied. The owner will need to provide the AME with the necessary information on the specific task being considered, and where applicable, the part involved by part number and serial number. Based on the inspection, the AME will determine whether a tolerance can be applied. This determination is well within the knowledge, experience and skill of an AME and their privileges of their AME licence.
2. Acceptable tolerance limits:
- a) Inspections performed every 12 months in accordance with STD 625 Appendix B; no greater than 15%.
- b) Out of phase task intervals performed in accordance with STD 625 Appendix C; no greater than 10%.
3. Aircraft inspection:
The purpose of the aircraft inspection is to ensure that it is in satisfactory condition to operate safely for the period of the selected tolerance. The depth of inspection is determined by the AME, including the task being considered, and is consistent with the general condition and utilization of the aircraft. If specialized work is required as part of the aircraft inspection, it must be completed by an appropriately rated AMO as described in section 571.04 of the CARs.
This inspection should also include a review of the aircraft technical records to help determine if the aircraft history, storage, utilization and previous defects, would have any impact on the safe operation.
4. Selection of the tolerance:
The results of the inspection will determine whether a tolerance can be applied within the acceptable limits above. It may be necessary for the AME to adjust the amount of tolerance based on these results. If the AME determines that a tolerance would have an effect to the safe operation of the aircraft, a tolerance cannot be applied.
5. Technical record and maintenance release:
If it is determined by the AME that the aircraft is in satisfactory condition to operate for the period of the selected tolerance, the AME shall record in the aircraft technical record the particulars of the maintenance performed including:
- the results of the inspection and technical record review;
- the tolerance selected;
- the specific maintenance task;
- the new interval; and
- signing of the maintenance release.
Based on the inspection results, if it is determined by the AME that a tolerance cannot be applied, the AME shall record in the aircraft technical record the particulars of the maintenance performed including:
- the results of the inspection and technical record review;
- a brief description of why a tolerance could not be applied; and
- signing of the applicable maintenance release.
Note: Each scheduled interval of a task is calculated from the time the task was last carried out, regardless if a tolerance is applied. For example, where a 12 month inspection is carried out at 13.8 months based on an applied 15% tolerance, the next inspection is due 12 months from the date of the inspection was completed.
Authorization to deviate from a maintenance schedule by TCCA:
When an AME is not available to inspect the aircraft and apply a tolerance to a maintenance schedule task, a request from an operator of a small private aircraft may be submitted to TCCA to deviate from the maintenance schedule requirements.
The request may be for a task that is coming due or that is overdue provided the aircraft has not flown as this would be a contravention to section 605.86 of the CARs.
The operator may apply via email to their respective regional TCCA office or Transport Canada Center (website link in resources section) and must provide a fully documented application which includes the reason and explanation for the need for a deviation, the specific task(s) being requested, and if applicable the part involved by part number and serial number, and sufficient justification in order to demonstrate that the aircraft is airworthy and in a satisfactory condition to operate for the period covered by the deviation.
An application should be submitted far enough in advance of the maintenance being required in order to allow for sufficient time to process the application, and state the proposed period for the deviation request and when the proposed completion of the task(s) by date, flying hours or cycles as applicable.
In no circumstance can a deviation authorization be applied to tasks mandated by airworthiness limitations or airworthiness directives.
Deviations may be authorized to tasks for the following required scheduled maintenance below:
- Required 12 month inspection performed in accordance with STD 625 Appendix B; and
- Out of phase maintenance task intervals performed in accordance with STD 625 Appendix C.
During the current COVID-19 pandemic, deviation requests received prior to June 30, 2023 will not require an aircraft inspection by an AME provided the aircraft owner’s request has sufficient justification that the aircraft is airworthy and that the deviation will not affect aviation safety. The following list of supporting evidence is non-exhaustive and TCCA may request additional information from the aircraft owner if required:
- details of the utilization during the past 12 months;
- details of the last maintenance was performed;
- details of the maintenance task and/or component (part number, serial number) being requested for deviation;
- that there are no outstanding aircraft defects; and
- statement from the aircraft owner that the aircraft manufacturer recommended servicing tasks have been performed and, if applicable, elementary work tasks have been completed.
There is no charge for an authorization to deviate and the deviation is not a permanent amendment to the aircraft’s maintenance schedule. Also, a deviation is not automatic and the request may be refused based on the review by TCCA and the affect to aviation safety.
Replacement of this notice:
TCCA is currently drafting a new AC on the subject and is anticipating publication before the expiry of this Notice.
- Section 605.86 of the CARs
- Subsections 625.86(8) and (9) of STD 625
- Technical Publication (TP) 13094 – Maintenance Schedule Approval Policy and Procedures Manual
- Maintenance and Manufacturing Staff Instruction MSI 66 – Authorization for Deviation from Scheduled Maintenance Requirements
- Internal Process Bulletin (IPB) 2020-11 Issue 03 – Interim Changes to Small Private Aircraft Maintenance Schedule Tolerance and Deviation Requests Due to the COVID-19 Pandemic
- TCCA offices: https://tc.canada.ca/en/aviation/civil-aviation-contacts-offices#headquarters_and_regional
If you have any questions, please contact:
Chief, Operational Airworthiness
Original signed by
Standards branch, Civil Aviation