Tap any paragraph to write a margin note. Your notes collect in the Desk below the text and file under cases with @. The side-by-side margin rail opens on a larger screen.

Code · CFR · Title 14 — Aeronautics and Space · Part 21 — Certification Procedures for Products and Articles · § 21.187

§ 21.187. Issue of multiple airworthiness certifications for restricted category aircraft.

222 words·~1 min read·/us/cfr/t14/s§ 21.187·

A research copy — for the controlling text, always check the official state or federal source. Not legal advice.

(a)An applicant for an airworthiness certificate in the restricted category, and in one or more other categories except primary category, is entitled to the certificate, if—
(1)The applicant shows compliance with the requirements for each category, when the aircraft is in the configuration for that category;
(2)The applicant shows that the aircraft can be converted from one category to another by removing or adding equipment by simple mechanical means;
(3)The aircraft complies with the applicable requirements of part 34 of this subchapter; and
(4)The airplane complies with the applicable requirements of part 38 of this subchapter.
(b)The operator of an aircraft certificated under this section must have the aircraft inspected by the FAA, or by a certificated mechanic with an appropriate airframe rating, to determine airworthiness each time the aircraft is converted from the restricted category to another category for the carriage of passengers for compensation or hire, unless the FAA finds this unnecessary for safety in a particular case.
(c)The aircraft complies with the applicable requirements of part 34. [Doc. No. 5085, 29 FR 14569, Oct. 24, 1964, as amended by Amdt. 21-68, 55 FR 32860, Aug. 10, 1990; Amdt. 21-70, 57 FR 41369, Sept. 9, 1992; Amdt. No. 21-107, 89 FR 12654, Feb. 16, 2024; Amdt. 21-109, 90 FR 35206, July 24, 2025]
★   the supreme law of the land   ★
Don't Tread on Me
E Pluribus Unum — out of many, one

"If you don't know your rights, you don't have any."

Marginalia · a citizen's law index
A research desk, not legal advice. Always read the cited source before relying on a summary.
Questions or an issue? support@self-law.org
disclaimerMarginalia is a research index, not a law firm. Nothing on this site is legal, tax, or financial advice and no attorney–client relationship is formed by using it. Statutes, regulations, and case law change; summaries, search results, AI output, and member posts may be incomplete, out of date, or wrong. Any interpretation drawn from material on this site should be validated by a licensed attorney in your jurisdiction before you act on it.