Is It Manufacturing or Is It Maintenance?

Is It Manufacturing Or Is It Maintenance? It’s all in the certification By Brian Whitehead February 2001 Manufacturing and maintenance have a lot in common. Many of the same tasks and procedures exist in both environments...



Is It Manufacturing Or Is It Maintenance?

It’s all in the certification

Brian WhiteheadBy Brian Whitehead

February 2001

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 Chapter 561 of the Airworthiness Manual (soon to be superseded by CAR 561) covers manufacturing, while CAR 571 addresses maintenance.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."

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