Is It Manufacturing or Is It Maintenance?

Manufacturing and maintenance have a lot in common. Many of the same tasks and procedures exist in both environments. Nevertheless, the CARs (Canadian Aviation Regulations) recognize a clear distinction between the two domains, and each is subject to its own set of rules. Chapter 561 of the Airworthiness Manual (soon to be superseded by CAR 561) covers manufacturing, while CAR 571 addresses maintenance. When working under CAR 561, the maintenance rules do not apply, and vice versa. That mutual exclusivity is achieved by definition: Manufacturing is defined as "the making, assembly and fabrication, other than the fabrication of parts as part of a repair, of aeronautical products, and includes, in the case of newly manufactured aircraft, any work performed on an aircraft prior to the issuance of the first certificate of airworthiness or export certificate of airworthiness."

Statement of conformity
New aeronautical products are certified by a statement of conformity, which may only be issued by the approved manufacturer. For a complete aircraft, the statement appears on the form currently known as the AI-100; for other products, it appears in the lower left block of the form 24-0078. We can consider the statement of conformity to be the product’s "birth certificate." All subsequent entries in the product technical records must calculate the "Time Since New" (TSN) from the time this certificate is issued.
After the statement of conformity for a new aircraft is signed, there may be a need for additional work before the C of A (Certificate of Airworthiness) is issued. Testing may indicate a need for adjustment or repair. The aircraft may require modification or configuration changes to meet customer requirements. While all these activities must be recorded in the aircraft technical records, so long as they occur before the C of A is issued they are not considered maintenance, and therefore are not subject to CAR 571. Instead, they are performed in accordance with the manufacturer’s approved procedures.
Once the C of A is issued, the situation changes. The definition of maintenance applies, and all work must now comply with CAR 571. That even applies to work that may look very much like manufacturing, such as the making of parts. CAR 571.06(4) permits the making of parts during repair or modification. The regulation sets no limits on the extent of such parts fabrication, but practical limits will obviously arise from the nature of the work. The maintainer must have access to the necessary data and equipment, for example.

Looks like manufacturing, but it’s maintenance
Aside from making parts, there are other kinds of manufacturing-like maintenance activities, such as assembling major components (propellers, modular engines or helicopter fuselages, for example) using manufacturer supplied parts. Several additional factors must be taken into account when doing this kind of work. If jigs and fixtures are required, the work may be specialized, and should only be done by an AMO with the applicable specialist rating. If the component being replaced bears the aircraft data plate, the aircraft identification requirements contained in Part 2 of the CARs must be observed. In the case of an airframe, engine, or propeller; the original technical records must be retained and must accompany the data plate.

Determining TSN
TSN is always calculated from the statement of conformity, even if all the original parts have been replaced. The CARs have no equivalent to FAR 91.421, which allows "zero time" to be recorded for a rebuilt engine, so the actual time should be entered. Where the TSN cannot be accurately determined, it should be recorded as unknown. Following repair or rebuilding, even if all new parts are installed, the finished item is still considered to be a used product, and the work must be certified by a maintenance release. It is not permissible to issue a statement of conformity for a "rebuild."

Fabricated parts
Where parts are fabricated, they must conform to the applicable data. This may be the original manufacturer’s specifications, or alternative data approved by STC or RDA. Locally-made parts must be clearly distinguishable from the original manufacturer’s parts. Typically, the same person will both fabricate and install the part, but single element items that are 100 percent inspectable may be made by one person and installed by another. The maintenance release for the installation also covers the making of the part, so the AME signing the release assumes responsibility for the entire job.
Where an AMO makes more complex items (let’s say a mod kit, made in accordance with an STC), it may be permissible for several individuals to take part in the fabrication, recording their actions on job cards. Each entry may constitute a partial maintenance release, with the final release being made by the AME responsible for the installation. The AME signing the final release is then responsible only for the actual installation, and can rely on the partial releases of the individual SCA holders for their portions of the work. It is important to understand that such a system is only acceptable when the part is both fabricated and installed by the same organization. It is suitable for organizations maintaining their own aircraft, and also for those providing "one stop shopping" for clients who bring aircraft in for repair or modification.

Repair parts provision has limits
What if an organization wants to make kits for installation by others? Well, that’s where we reach the limits of the "repair parts" provision. CAR 571.11 requires anyone signing a maintenance release to "personally observe the work," so they may only assume responsibility for parts made by others if the parts are 100 percent inspectable. Items like our mod kit example do not meet that criterion, so a separate certification is needed. A maintenance release won’t do, because the only actual maintenance being done is the installation, so the only thing left is a statement of conformity. And the only way to get the authority for that, is to obtain a CAR 561 manufacturing approval.
So, there we have it. Some things may only be done by manufacturers, some things only by maintainers, and some things by both. The main distinguishing feature is the certification used. If you have to make a part, and you do not hold a manufacturing approval, certifying the part itself is out of the question, so you must certify the entire job by issuing a maintenance release for the installation. To do that, you must be able to show compliance with all the applicable maintenance regulations, including those dealing with engineering data, record keeping, and product identification.