FAR 21.25 — Restricted Category Type Certificates
FAR 21.25 explains how aircraft qualify for a restricted category type certificate for special purpose operations like agriculture, firefighting, and patrol.
In Plain English
FAR 21.25 sets the rules for issuing a type certificate to an aircraft in the restricted category — aircraft built or modified for special purpose operations rather than normal passenger or cargo flying.
To qualify, the applicant must show the aircraft meets Part 36 noise requirements and has no feature that makes it unsafe within its intended limitations. The aircraft must also either:
- Meet the airworthiness requirements of another category (except primary or light-sport), minus any requirements the FAA finds inappropriate for the special purpose, or
- Be a type manufactured for and accepted by the U.S. Armed Forces, with an acceptable military service history, and be capable (or modified to be capable) of the special purpose operation.
Approved special purposes include:
- Agricultural work (spraying, dusting, seeding, pest/animal control, frost control)
- Forest and wildlife conservation (firefighting, fish spotting, oil spill response)
- Aerial surveying and patrolling (pipelines, powerlines, railroads)
- Weather control (cloud seeding)
- Aerial advertising (skywriting, banner towing)
- Other uses like external-load rotorcraft ops, target towing, SAR, glider towing, and Alaskan fuel hauling
This matters operationally because restricted category aircraft are limited to their certificated special purpose and generally cannot carry persons or property for hire outside that mission.
Regulation Text
14 CFR § 21.25§ 21.25 Issue of type certificate: restricted category aircraft.
(a) An applicant is entitled to a type certificate for an aircraft in the restricted category for special purpose operations if the applicant shows compliance with the applicable noise requirements of part 36 of this chapter, and if the applicant shows that no feature or characteristic of the aircraft makes it unsafe when it is operated under the limitations prescribed for its intended use, and that aircraft—
(1) Meets the airworthiness requirements of an aircraft category, other than primary category or light-sport category, except those requirements that the FAA finds inappropriate for the special purpose operation for which the aircraft is to be used; or
(2) Is of a type that—
(i) Has been manufactured in accordance with the requirements of, and accepted for use by, the U.S. Armed Forces;
(ii) Has a service history with the U.S. Armed Forces acceptable to the FAA; and
(iii) Has been found capable by the FAA of performing, or has been modified to perform, the special purpose operation for which the aircraft is to be used.
(b) Restricted category aircraft can be approved for:
(1) Agricultural use, for one or more of the following special purpose operations, including—
(i) Spraying, dusting, and seeding;
(ii) Livestock and predatory animal control;
(iii) Insect control;
(iv) Dust control; or
(v) Fruit drying and frost control.
(2) Forest and wildlife conservation, for one or more of the following special purpose operations, including—
(i) Aerial dispensing of firefighting materials;
(ii) Fish spotting;
(iii) Wild animal survey; or
(iv) Oil spill response.
(3) Aerial surveying, for one or more of the following special purpose operations, including—
(i) Aerial imaging and mapping;
(ii) Oil, gas, and mineral exploration;
(iii) Atmospheric survey and research;
(iv) Geophysical and electromagnetic survey;
(v) Oceanic survey; or
(vi) Airborne measurement of navigation signals.
(4) Patrolling, for one or more of the following special purpose operations, including—
(i) Pipelines;
(ii) Powerlines;
(iii) Data transmission lines and towers;
(iv) Railroads;
(v) Canals; or
(vi) Harbors.
(5) Weather control, including the special purpose operation of cloud seeding.
(6) Aerial advertising, for one or more of the following special purpose operations, including—
(i) Skywriting;
(ii) Banner towing;
(iii) Displaying airborne signs; or
(iv) Public address systems.
(7) Other special purpose operations, including—
(i) Rotorcraft external-load operations conducted under part 133 of this chapter;
(ii) Carriage of cargo incidental to the owner's or operator's business;
(iii) Target towing;
(iv) Search and rescue operations;
(v) Glider towing;
(vi) Alaskan fuel hauling;
(vii) Alaskan fixed-wing external load operations;
(viii) Space vehicle launch; or
(ix) Any other special purpose operation specified by the FAA.
[Docket No. FAA-2023-1377, Amdt. No. 21-109, 90 FR 35204, July 24, 2025]
Oral Exam Questions a DPE Might Ask
Q1What is a restricted category aircraft and how does it get type certificated?
Per FAR 21.25, a restricted category aircraft is one type certificated for a special purpose operation. The applicant must show compliance with Part 36 noise rules, no unsafe features for the intended use, and either meet another category's airworthiness standards (except primary or light-sport) or be a former U.S. military type accepted by the FAA.
Q2Give some examples of special purpose operations approved under the restricted category.
FAR 21.25(b) lists agricultural ops (spraying, dusting, seeding), forest and wildlife conservation (aerial firefighting, oil spill response), aerial surveying, patrolling pipelines or powerlines, weather control like cloud seeding, aerial advertising including banner towing, and other uses such as external-load rotorcraft ops, glider towing, and search and rescue.
Q3Can a former military aircraft be type certificated in the restricted category?
Yes. Under FAR 21.25(a)(2), an aircraft manufactured for and accepted by the U.S. Armed Forces, with a service history acceptable to the FAA, can be certificated in the restricted category if the FAA finds it capable of (or modified to perform) the intended special purpose operation.
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Related Sections in Part 21