FAR 21.184 — Primary Category Airworthiness
FAR 21.184 explains how to obtain a special airworthiness certificate for primary category aircraft, including new, imported, and converted standard-category aircraft.
In Plain English
FAR 21.184 sets out how an applicant gets a special airworthiness certificate – primary category for aircraft meeting the small, simple aircraft criteria of § 21.24(a)(1). There are four pathways:
- New, U.S.-built aircraft (a): If built under a production certificate (including kit-assembled aircraft built under the PC holder's supervision and quality control), the applicant is entitled to a certificate without further showing, though the FAA may inspect for type-design conformity and safe condition.
- Imported aircraft (b): Type certificated under § 21.29, the foreign civil airworthiness authority must certify, and the FAA must find after inspection, that the aircraft conforms to the approved type design and is safe to operate.
- Conversion from standard category (c): An aircraft holding a current standard airworthiness certificate (conforms to its normal/utility/acrobatic type design, complies with all ADs, inspected airworthy within the last 12 calendar months per § 91.409(a)(1)) can be converted via the supplemental type certification process.
- All other cases (d): The applicant must show conformity to an approved primary/normal/utility/acrobatic type design with all ADs complied with, an annual inspection within 12 calendar months, and FAA finding of safe condition.
Finally, paragraph (e) makes clear a primary category aircraft may hold only one airworthiness certificate — you can't dual-certify it in another category. This matters operationally because primary category aircraft have specific limitations (e.g., on commercial use and maintenance), and the certification path determines what documentation and inspections are required before flight.
Regulation Text
14 CFR § 21.184§ 21.184 Issue of special airworthiness certificates for primary category aircraft.
(a)An applicant for an original, special airworthiness certificate-primary category for a new aircraft that meets the criteria of § 21.24(a)(1), manufactured under a production certificate, including aircraft assembled by another person from a kit provided by the holder of the production certificate and under the supervision and quality control of that holder, is entitled to a special airworthiness certificate without further showing, except that the FAA may inspect the aircraft to determine conformity to the type design and condition for safe operation.
(b)An applicant for a special airworthiness certificate-primary category for an imported aircraft type certificated under § 21.29 is entitled to a special airworthiness certificate if the civil airworthiness authority of the country in which the aircraft was manufactured certifies, and the FAA finds after inspection, that the aircraft conforms to an approved type design that meets the criteria of § 21.24(a)(1) and is in a condition for safe operation.
(c)An applicant for a special airworthiness certificate-primary category, for an aircraft having a current standard airworthiness certificate that meets the criteria of § 21.24(a)(1), may obtain the primary category certificate in exchange for its standard airworthiness certificate through the supplemental type certification process. For the purposes of this paragraph, a current standard airworthiness certificate means that the aircraft conforms to its approved normal, utility, or acrobatic type design, complies with all applicable airworthiness directives, has been inspected and found airworthy within the last 12 calendar months in accordance with § 91.409(a)(1) of this chapter, and is found to be in a condition for safe operation by the FAA.
(d)An applicant for a special airworthiness certificate-primary category for an aircraft that meets the criteria of § 21.24(a)(1), and is not covered by paragraph (a), (b), or (c) of this section, is entitled to a special airworthiness certificate if—
(1) The applicant presents evidence to the FAA that the aircraft conforms to an approved primary, normal, utility, or acrobatic type design, including compliance with all applicable airworthiness directives;
(2) The aircraft has been inspected and found airworthy within the past 12 calendar months in accordance with § 91.409(a)(1) of this chapter and;
(3) The aircraft is found by the FAA to conform to an approved type design and to be in a condition for safe operation.
(e)in the primary category and any other category will not be issued; a primary category aircraft may hold only one airworthiness certificate.
[Doc. No. 23345, 57 FR 41368, Sept. 9, 1992, as amended by Amdt. 21-70, 57 FR 43776, Sept. 22, 1992]
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Oral Exam Questions a DPE Might Ask
Q1What are the ways an applicant can obtain a special airworthiness certificate in the primary category?
Per FAR 21.184, there are four paths: a new aircraft built under a production certificate (including supervised kit-builds), an imported aircraft type certificated under § 21.29, conversion from a current standard airworthiness certificate via the STC process, or any other aircraft meeting § 21.24(a)(1) by showing type-design conformity, AD compliance, and a current annual inspection.
Q2Can a primary category aircraft also hold a standard airworthiness certificate at the same time?
No. FAR 21.184(e) states that a primary category aircraft may hold only one airworthiness certificate; dual certification in primary and another category is not issued.
Q3If converting an aircraft with a standard airworthiness certificate to primary category, what conditions must the aircraft meet?
Under FAR 21.184(c), the aircraft must currently conform to its approved normal, utility, or acrobatic type design, comply with all applicable ADs, have been inspected and found airworthy within the last 12 calendar months per § 91.409(a)(1), be found in safe condition by the FAA, and the conversion is accomplished through the supplemental type certification process.
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§21.15 Type Certificate Application
FAA application form, aircraft drawings, and engine data
§21.17 Certification Basis
Applicable airworthiness, noise, and emission rules
§21.20 Compliance Showing
How applicants show compliance to the FAA
§21.31 Type Design
Drawings, specifications, dimensions, and limitations
§21.41 Type Certificate
What the certificate includes once the design is approved
§21.47 Type Certificate Transferability
Transfer and licensing notices for FAA type certificates
Related Sections in Part 21