FAR 21.177 — Airworthiness Certificate Amendment
FAR 21.177 explains how an airworthiness certificate can be amended or modified—only by formal application to the FAA. Quick guide for pilot students.
In Plain English
FAR 21.177 is short but important: an airworthiness certificate can only be amended or modified by submitting an application to the FAA. In other words, neither the owner, operator, nor a mechanic can simply change what's printed on the certificate on their own — any change has to go through the FAA's formal process.
Why it matters operationally:
- The airworthiness certificate is one of the required documents that must be onboard the aircraft (remember ARROW).
- If the aircraft's category, type, or other certificated details change (for example, after a major modification or change in operating category), the certificate must be updated through the FAA — not by hand or by a third party.
- Flying with an altered or unauthorized certificate could render the aircraft not airworthy and the flight illegal.
Bottom line: any change to the airworthiness certificate is an FAA-only action, initiated by an application from the owner or operator.
Regulation Text
14 CFR § 21.177§ 21.177 Amendment or modification.
An airworthiness certificate may be amended or modified only upon application to the FAA.
Oral Exam Questions a DPE Might Ask
Q1Who is allowed to amend or modify an aircraft's airworthiness certificate?
Per FAR 21.177, only the FAA may amend or modify an airworthiness certificate, and only after the owner or operator submits an application requesting the change.
Q2If your aircraft undergoes a change that affects its airworthiness certificate, what's the proper procedure?
FAR 21.177 requires that you apply to the FAA to have the certificate amended or modified — you cannot alter the certificate yourself or have a mechanic do it.
Q3Can an A&P mechanic or IA modify the airworthiness certificate after a major alteration?
No. Under FAR 21.177, any amendment or modification to an airworthiness certificate must be made by the FAA upon application; mechanics have no authority to change the certificate itself.
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Related Sections in Part 21