Maintenance and Certification Maintenance and Certification

Maintenance Schedule Approval: What is it and how do you get one?


Section 605.86 of the Canadian Aviation Regulations (CAR) requires that all aircraft, other than ultra-light or hang-gliders, be maintained in accordance with a maintenance schedule that is approved by the Minister and that meets the requirements of Standard 625—Aircraft Equipment and Maintenance Standard. Standard 625.86 and Standard 625 Appendices B, C and D contain the specific requirements pertaining to the differing aircraft types and operations. Standard 625 Appendix B contains a useful and convenient chart that summarizes the requirements for the various aircraft types and operations.

There are essentially two types of maintenance schedules established by CAR 605.86. The first type, authorized by paragraph 605.86(1)(a) of the CARs, is considered to be “pre-approved” by the Minister and may be used without the need to submit any further documentation. The second type of maintenance schedule requires review by, and approval from Transport Canada Civil Aviation (TCCA) under subsection 605.86(2) of the CARs. This article will focus more on the second type. The process for developing this type of maintenance schedule and obtaining a Maintenance Schedule Approval (MSA) from TCCA will also be described.

Pre-Approved Schedules

Owners of small non-commercial aircraft and balloons (excluding pressurized turbine-powered aircraft) may choose to use the maintenance inspection schedule described in Standard 625 Appendix B, Part I or II, as applicable. The aircraft must undergo a complete inspection, as described by Appendix B, every 12 calendar months and the owner must also comply with Appendix C with respect to the out of phase tasks and equipment maintenance requirements.

The aircraft owner is required by CAR 605.94(1) to make an entry in the technical record stating that the aircraft is maintained pursuant to the requirements in Appendix B, Part I or II.

Schedules that require Transport Canada Approval

All other aircraft operators require an MSA, approved by the Minister under subsection 625.86(2) of the CARs. Depending on the aircraft type and operation, operators may chose to use either Appendices B and C or Appendices C and D of Standard 625 to develop their respective schedules.

The Appendix C items are out of phase tasks and equipment maintenance tasks, while Appendices B and D pertain to scheduled inspection tasks. The proposed maintenance schedule must contain the instructions and procedures for the performance of maintenance on the particular make and model of aircraft in the form of a checklist. The checklist will contain the items to be maintained, the nature or type of inspection or maintenance task to be performed, the proposed interval for the task and any tolerances applicable to the task.

Developing a maintenance schedule

When developing the aircraft maintenance schedule, the operator must consider all tasks from the manufacturer’s recommendations and include any additional items necessary to ensure compliance with airworthiness limitations, such as component life limits, etc. The schedule must also take into account the aircraft’s operational environment. For example, aircraft engaged in agricultural operations may require additional engine, landing gear and corrosion inspection tasks or increased task intervals. In addition, specific operational requirements, such as those for Instrument Flight Rules, Extended Range Operations, Category II & III approach minima, etc., may necessitate additional equipment maintenance requirements.

The applicant must review and evaluate any type certificate holder’s recommendations and all maintenance requirements resulting from any modifications or repairs. This includes the recommendations issued by the type certificate holder (airframe, engine, or propeller), in the form of Instructions for Continued Airworthiness (ICA), Service Bulletins, and Service Letters, etc. The applicant must also consider any additional maintenance task recommendations issued by the holders of type design change approval documents, such as Supplementary Type Certificates (STC), Repair Design Approvals (RDA), etc.

The development of the maintenance schedule must be based on a Maintenance Review Board Report (MRBR), where one exists. Only when no MRBR exists for the aircraft can the owner base the development of the aircraft’ s maintenance schedule on an alternative basis, such as the aircraft manufacturer’s recommendations or on another Canadian operator’s approved program, provided there are significant similarities between the types of operations. It may also be approved based on other data, such as schedules approved by other airworthiness authorities. When the owner or operator wishes to base the maintenance schedule on data other than the aircraft manufacturer’s recommendations, the onus is on the owner to satisfy the Minister that the proposed basis is more appropriate for its particular operation.

Transport Canada (TC) has published TP 13094E as guidance material in order to assist owners and operators to develop maintenance schedules and it is available at no cost on the TC Web site at:

The Application Procedure

The applicant submits the appropriate completed application form to their Principal Maintenance Inspector (PMI) or to the local TC Centre (TCC), along with the fee prescribed by CAR 104 Schedule IV. Form 24-0055A is applicable to small aircraft and Form 24-0055B is applicable to large aircraft. The forms are available on the TC Web site at the following link.

The forms contain an expanding checklist for adding tasks; however, the data cannot be saved using the on-line form. The applicant would therefore have to re-type the data each time they sought to make revisions to the schedule. For that reason, it may be advisable for the applicant to create their own Table 1 and 3 checklist documents for attachment to the application form, in order to facilitate future amendments.

The first part of the form is used to record basic information, such as operator information, aircraft type and model, type of operation, annual utilization and it contains a section reserved for recording the applicant’s signature and another for recording the maintenance schedule revision status.

The next section, Table 1, records the details of any required inspections, the schedule interval and any applicable tolerance to the interval. This section also records the details of the aircraft scheduled check cycle and an explanation of how the checks or series of checks are applied and interact with each other.

The operator must also complete Table 3, which describes the out of phase tasks and any equipment maintenance requirements. The applicant must review the list of out of phase items required by Standard 625 Appendix C for applicability and include those that are applicable.

The applicant must ensure to include all required aircraft and component inspections, component overhaul times, engine and propeller overhaul in Table 3 and any other inspections that are not included in the scheduled inspections in Table 1. In Table 2, the operator must provide a list of reference documents that were used as source documents to develop the maintenance schedule.

Finally, in the last section, the applicant must specify if it is a new or experienced operator of the aircraft type and what basis was chosen for the development of the maintenance schedule.

Approval and Revisions

Upon receipt of a maintenance schedule approval request, TC will perform a review of the application and supporting documentation. The depth of review required for TC approval will depend on the applicant’s individual circumstances and the basis that was used to develop the applicant’s maintenance schedule. TC will also advise the applicant if any additional documents are required and or if a site visit will be necessary.

The items that will be considered during the approval process include: the type of operation, environmental factors, the aircraft maintenance history, the age of the aircraft, the experience of the operating personnel, any maintenance schedules for similar aircraft types already in use by the operator, any additional equipment required by regulations, any airworthiness limitations, Supplemental Inspection Documents (SID), Corrosion Prevention Control Programs (CPCP) and any previous repairs to damaged tolerant structures. In addition to the airframe and systems, the schedule must also consider the engines, propellers, appliances, survival equipment, emergency equipment, etc., and must take into account any modifications made to the aircraft.

TC must approve the initial maintenance schedule and all subsequent amendments to the schedule. Except where specifically authorized in the operator’s MCM, TC must approve all maintenance schedule amendments that relate to changes in the aircraft’s operational role, for deletion of tasks, increase in task intervals, or any other significant changes. Prior approval is not required, however, for the addition of tasks or reductions of task intervals, the operator must notify TC at the earliest convenient opportunity.

Emergency Locator Transmitter Programmable Dongle

The following article was prepared by the National Aircraft Certification Branch of Transport Canada Civil Aviation as a result of an Aviation Safety Information letter from the Transportation Safety Board of Canada (TSB).

On November 12, 2009, a privately owned and operated Robinson helicopter R44II took off from a worksite in Baie Trinité with a pilot and two passengers on board on a return flight to Baie Comeau, Qué. At 12:49 Eastern Standard Time (EST), the helicopter collided with one of two ground wires on top of a transmission line over the Franquelin River, 10 NM from Baie Comeau. The helicopter crashed on the riverbank and was destroyed. The pilot did not survive and both passengers were seriously injured. A passerby discovered the wreckage and sought help.

An emergency locator transmitter (ELT), manufactured in France by Kannad, model 406 AF-Compact (part number S1840501-01, serial number 2619976-0123), was installed in the helicopter. The ELT was capable of transmitting data on a 406 Mhz carrier frequency and audio on a 121.5 MHz carrier frequency. Upon acquiring the helicopter, the owner ensured the ELT was programmed and registered, as required. The unit was tested and found to be serviceable in January 2009.

During the accident investigation, the Transportation Safety Board (TSB) tested the helicopter’s ELT in order to verify its serviceability. Although the unit was serviceable and had activated on impact, the ELT unit antenna had been severed.The COSPAS-SARSAT Canadian Mission Control Centre (CMCC) confirmed that no ELT signal had been detected by the satellite following the time of the accident. This likely explained the severed antenna, which rendered the signal weak, and the wreckage or surrounding terrain possibly shielded the localized signal.

It was also determined that the occurrence ELT was transmitting on the ‘Test User Protocol’ mode, a country code of 227 (France) and an identification code different from the beacon identification code included in the Canadian Beacon Registry (CBR) database.

Upon further investigation, it was found that this ELT was coupled with an out-of-factory programmable dongle containing a default manufacturer’s code. A dongle is a connector plug, which contains a microchip. Refer to Figure 1.

Dongles are useful in fleets when a company needs to service an aircraft ELT. When a dongle is installed, it allows the ELT to be easily repaired or replaced without putting the aircraft out of service.

Photo of  programmable dongle installed in line with wiring for the remote control switch
Figure 1, ELT & programmable dongle

Information specific to an ELT, such as the owner and aircraft, is programmed and stored in the dongle’s non-volatile memory (NVM). When a new or replaced ELT is connected to the dongle, and the ELT is switched from the ‘OFF’ to the ‘ARM’ position, the dongle will automatically reprogram the ELT with the information stored in its NVM, including the ELT’s 15 digits hexadecimal identification code (if the dongle is programmed correctly).

Photo of dongle with three wires connector
Dongle with three wires connector

In this particular accident, although the ELT was properly registered, programmed and tested serviceable in January 2009, the dongle had not been reprogrammed with the helicopter’s specific information. Maintenance personnel did not know the dongle was programmable and the avionic shop was not aware that this particular ELT installation included a programmable dongle.

Any transmission on the Test User Protocol mode, if received by the COSPAS-SARSAT CMCC may not be treated as though it had been received in the normal mode.

Since 406 MHz ELTs are new to the industry altogether, Transport Canada (TC) and the TSB recommend that aircraft operators, owners, maintenance and avionics facilities be aware of the purpose of the programmable dongle and the importance of ensuring that the programmed information is correct. Dongles need to be reprogrammed when the aircraft country of registration changes.

TC recommends checking if a dongle is installed and programmed correctly at the next ELT servicing.

Elementary Work Entries in the Journey Log

by Steve McLeod, Civil Aviation Safety Inspector, Aircraft Maintenance and Manufacturing, Sudbury Transport Canada Centre, Ontario Region, Civil Aviation, Transport Canada

During ramp inspections of CAR 703 commercial floatplane operators by Transport Canada inspectors, one issue was prevalent with each aircraft inspected. All the pilots interviewed during the ramp inspection of their aircraft acknowledged that they removed and installed passenger seats, but none of them made the corresponding journey log entry for the work completed. Of the elementary work tasks listed in CAR 625, Appendix A, "the removal and replacement of role equipment designed for rapid removal and replacement", in this case aircraft passenger seats, is one of the most common tasks performed by commercial floatplane operators.

Depending on the nature of the flight, the aircraft will either be configured for cargo, passengers or both. Aircraft like the DHC-2 Beaver use seats that have a quick disconnect, allowing them to be removed from the aircraft, while the DHC-3 Otter and the Beech 18 have seats that fold up along the side of the fuselage. Regardless of the aircraft and seat attachment means, the performance of any task designated as elementary work shall be entered in the journey log of the aircraft in accordance with CAR 605.94, Schedule I. This entry is required as soon as it is practical to do so, once the elementary work is performed, before the next flight, at the latest.

Seat installation becomes more of an issue when we refer to Airworthiness Directive (AD) CF-85-03R1, applicable to the DHC-3 Otter cabin utility seats. This AD addresses the disengagement of the front leg of the seat from the keyhole slot in the floor, which creates a hazard to the occupants. There is a check of the forward seat leg associated with this AD that ensures the front leg is secure; it is carried out at intervals not to exceed 100 hr time in service and after each time the seats are moved from the stowed position to the deployed position. If, during the check, the seat leg can be released from the keyhole slot, the seat must be removed from service. A pilot briefed on the procedure can carry out this inspection.

A modification from the manufacturer, adding a positive lock to the front leg of the seat, provides relief from the check outlined in the AD. However, should the forward lock become unserviceable, the check outlined in the AD must be carried out.

In addition to the seat removal and installation, there is a requirement to indicate the correct aircraft configuration for weight and balance purposes. Typically an aircraft is weighed with the seats installed and are therefore included in the basic empty weight of the aircraft. If the seats are removed to change the configuration of the aircraft, the weight and balance have to be amended. Operators who frequently take seats in and out will have different aircraft configurations already calculated, complete with the required maintenance release. When the aircraft configuration is changed, the applicable weight and balance addendum is used to indicate the basic empty weight and centre of gravity for that configuration. In addition to the elementary task entry, CAR 571, Appendix C (3)(b) requires the current applicable addendum to be identified in the aircraft journey log.

CAR 703 operators include the policies and procedures for the training and authorization to perform elementary work and servicing in their Maintenance Control Manuals. Initial and recurrent training should include the recording requirements of the performance of elementary work and servicing and the corresponding weight and balance requirements as applicable. The person responsible for maintenance during their review of aircraft journey logbooks will be able to determine if the required elementary work and applicable weight and balance addendum entries are being made.

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