What effectivity answers
Effectivity is the applicability of a part or instruction to a defined aircraft, engine, component or configuration. A parts catalog entry may be limited by aircraft manufacturer serial number, modification status, installed system or another criterion. In practical buying terms, effectivity answers whether the candidate part belongs on the particular asset in front of the maintenance team—not merely whether it belongs somewhere in the same aircraft family.
This matters because a catalog description may stay similar while part numbers, dash numbers or approved alternatives change. A part removed from one aircraft can look identical to a candidate for another but differ in the relevant configuration. Buyers can collect the identifiers and supporting documents; the operator or authorized maintenance organization must make the final installation-eligibility determination using current applicable data.
The identifiers worth collecting
Start with the exact requested part number and the source used to identify it, such as the applicable illustrated parts catalog or maintenance data. Then identify the aircraft model and manufacturer serial number. For an engine or serialized assembly, include its model and serial number as relevant. If a service bulletin, modification or airworthiness directive affects the configuration, tell the sourcing team which status the maintenance team has confirmed. The supplier need not decide effectivity from a broad aircraft label alone.
If an alternate or superseding number is offered, ask what relationship is being claimed and request the supporting reference. A proposed substitute may be valid only for certain serial ranges or configurations. Record the offered item’s exact part and serial numbers, condition and accompanying documentation so the technical reviewer can compare like with like.
Paperwork supports, but does not replace, the decision
Release and traceability records are essential evidence, yet they answer different questions from effectivity. FAA AC 20-62E addresses quality, eligibility and traceability when evaluating replacement parts for U.S. type-certificated products. Under EASA guidance, Form 1 helps the recipient determine airworthiness approval status but is not authorization to install an item on a specified aircraft, engine or propeller. In both cases, the installation decision belongs with the authorized party applying the relevant technical data.
An efficient request therefore includes two parallel tracks: source the candidate and verify its fit. Ask suppliers for clear identifiers and records early, while the maintenance team checks applicability. If the answer is uncertain, label it as unresolved in the RFQ rather than presenting a possible match as an approved substitute. That small distinction protects both the buying process and the maintenance decision.
A practical handoff is to attach the offered part number and documentation to the original requirement, record the applicable aircraft or engine identifiers, and ask the designated technical reviewer for a clear accept, reject or more-information decision. That preserves the reasoning behind the purchase and avoids turning a sales description into an engineering conclusion.
Source material
These references provide general context. Confirm item-specific requirements with the applicable records and qualified teams.