FAR 21.17 — Type Certificate Applicable Regulations
FAR 21.17 explains which airworthiness rules apply to a type certificate application, how long applications stay valid, and special category requirements.
In Plain English
FAR 21.17 tells a type certificate applicant which airworthiness rules their aircraft, engine, or propeller must meet. The general rule: the product must comply with the regulations in effect on the date of application, plus any special conditions the FAA prescribes — unless the FAA specifies otherwise or the applicant elects (or is required) to comply with a later amendment.
Key points:
- Special classes (gliders, airships, other nonconventional aircraft) without dedicated standards must meet portions of Parts 23, 25, 27, 29, 31, 33, and 35 the FAA finds appropriate, or equivalent safety criteria.
- Application validity: 5 years for transport category aircraft, 3 years for any other type certificate, unless the FAA approves a longer period.
- If the certificate isn't issued in time, the applicant may file a new application under current rules, or file for an extension using rules effective no earlier than the validity period before issuance.
- If an applicant elects a later amendment, they must also comply with any directly related amendment the FAA identifies.
- Primary category aircraft must meet applicable parts of 23, 27, 31, 33, and 35, plus Part 36 noise standards.
This matters because it locks in the certification basis — the exact rule set the manufacturer must prove compliance with — which downstream affects every aircraft built under that type design.
Regulation Text
14 CFR § 21.17§ 21.17 Designation of applicable regulations.
(a) Except as provided in §§ 25.2, 27.2, and 29.2 of this subchapter, and in parts 26, 34, 36, and 38 of this subchapter, an applicant for a type certificate must show that the aircraft, aircraft engine, or propeller concerned meets—
(1) The applicable requirements of this subchapter that are effective on the date of application for that certificate unless—
(i) Otherwise specified by the FAA; or
(ii) Compliance with later effective amendments is elected or required under this section; and
(2) Any special conditions prescribed by the FAA.
(b) For special classes of aircraft, including the engines and propellers installed thereon (e.g., gliders, airships, and other nonconventional aircraft), for which airworthiness standards have not been issued under this subchapter, the applicable requirements will be the portions of those other airworthiness requirements contained in Parts 23, 25, 27, 29, 31, 33, and 35 found by the FAA to be appropriate for the aircraft and applicable to a specific type design, or such airworthiness criteria as the FAA may find provide an equivalent level of safety to those parts.
(c) An application for type certification of a transport category aircraft is effective for 5 years and an application for any other type certificate is effective for 3 years, unless an applicant shows at the time of application that his product requires a longer period of time for design, development, and testing, and the FAA approves a longer period.
(d) In a case where a type certificate has not been issued, or it is clear that a type certificate will not be issued, within the time limit established under paragraph (c) of this section, the applicant may—
(1) File a new application for a type certificate and comply with all the provisions of paragraph (a) of this section applicable to an original application; or
(2) File for an extension of the original application and comply with the applicable airworthiness requirements of this subchapter that were effective on a date, to be selected by the applicant, not earlier than the date which precedes the date of issue of the type certificate by the time limit established under paragraph (c) of this section for the original application.
(e) If an applicant elects to comply with an amendment to this subchapter that is effective after the filing of the application for a type certificate, he must also comply with any other amendment that the FAA finds is directly related.
(f) For primary category aircraft, the requirements are:
(1) The applicable airworthiness requirements contained in parts 23, 27, 31, 33, and 35 of this subchapter, or such other airworthiness criteria as the FAA may find appropriate and applicable to the specific design and intended use and provide a level of safety acceptable to the FAA.
(2) The noise standards of part 36 applicable to primary category aircraft.
[Doc. No. 5085, 29 FR 14564, Oct. 24, 1964, as amended by Amdt. 21-19, 32 FR 17851, Dec. 13, 1967; Amdt. 21-24, 34 FR 364, Jan. 10, 1969; Amdt. 21-42, 40 FR 1033, Jan. 6, 1975; Amdt. 21-58, 50 FR 46877, Nov. 13, 1985; Amdt. 21-60, 52 FR 8042, Mar. 13, 1987; Amdt. 21-68, 55 FR 32860, Aug. 10, 1990; Amdt. 21-69, 56 FR 41051, Aug. 16, 1991; Amdt. 21-70, 57 FR 41367, Sept. 9, 1992; Amdt. 21-90, 72 FR 63404, Nov. 8, 2007; Doc. No. FAA-2015-1621, Amdt. 21-100, 81 FR 96688, Dec. 30, 2016; Amdt. No. 21-107, 89 FR 12653, Feb. 16, 2024]
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Oral Exam Questions a DPE Might Ask
Q1When an applicant files for a type certificate, which airworthiness regulations apply to the product?
Per FAR 21.17(a), the applicable requirements are those in effect on the date of application, plus any special conditions prescribed by the FAA, unless the FAA specifies otherwise or the applicant elects later amendments.
Q2How long is a type certificate application effective, and what happens if the certificate isn't issued in that time?
FAR 21.17(c) makes a transport category application effective for 5 years and others for 3 years. Under FAR 21.17(d), the applicant may file a new application or request an extension using a later compliance date selected within the original time limit.
Q3How does the FAA designate applicable rules for nonconventional aircraft like gliders or airships?
FAR 21.17(b) states that for special classes without dedicated airworthiness standards, the FAA applies appropriate portions of Parts 23, 25, 27, 29, 31, 33, and 35, or alternative criteria providing an equivalent level of safety.
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§21.15 Type Certificate Application
FAA application form, aircraft drawings, and engine data
§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
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