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Quality System Changes

FAR 21.150 — Quality System Changes

FAR 21.150 requires production certificate holders to submit quality system changes for FAA review and immediately report changes affecting airworthiness.

In Plain English

FAR 21.150 governs what happens when a production certificate (PC) holder makes changes to their quality system after the certificate has been issued. The quality system is the set of procedures and controls a manufacturer uses to ensure every aircraft, engine, propeller, or part that leaves the factory conforms to its approved design and is in a condition for safe operation.

The rule has two requirements:

  • FAA review of all changes: Every change to the quality system is subject to FAA review. The manufacturer cannot make quality system changes in isolation — the FAA retains oversight.
  • Immediate written notification: The PC holder must immediately notify the FAA in writing of any change that may affect the inspection, conformity, or airworthiness of its product or article.

Why it matters operationally: as a pilot, you trust that a type-certificated aircraft was built exactly to its approved design. This regulation is one of the safeguards that keeps that trust intact, ensuring manufacturing changes don't quietly degrade the airworthiness of aircraft you fly.

Regulation Text
14 CFR § 21.150
§ 21.150 Changes in quality system. After the issuance of a production certificate— (a) Each change to the quality system is subject to review by the FAA; and (b) The holder of a production certificate must immediately notify the FAA, in writing, of any change that may affect the inspection, conformity, or airworthiness of its product or article.
Oral Exam Questions a DPE Might Ask
Q1If a manufacturer with a production certificate changes its quality system, what must it do?
Per FAR 21.150, each change is subject to FAA review, and the holder must immediately notify the FAA in writing of any change that may affect the inspection, conformity, or airworthiness of its product or article.
Q2Under FAR 21.150, when must a production certificate holder notify the FAA of a quality system change?
FAR 21.150 requires the holder to notify the FAA immediately, and in writing, whenever a change may affect inspection, conformity, or airworthiness.
Q3Who has oversight authority over changes to a production certificate holder's quality system?
The FAA. Under FAR 21.150(a), each change to the quality system is subject to FAA review after the production certificate is issued.
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Related Sections in Part 21
§ 21.1
Certification Procedures
§ 21.101
Type Certificate Changes
§ 21.11
Type Certificate Applicability
§ 21.111
STC Applicability
§ 21.113
Supplemental Type Certificate
§ 21.115
Supplemental Type Certificates
§ 21.117
Supplemental Type Certificates
§ 21.119
STC Privileges
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FAR 21.150 — Changes in Quality System