14 C.F.R. § 21.25

(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.