14 CFR 91.313 - Restricted category civil aircraft: Operating limitations.
(1) For other than the special purpose for which it is certificated; or
(2) In an operation other than one necessary to accomplish the work activity directly associated with that special purpose.
(b) For the purpose of paragraph (a) of this section, operating a restricted category civil aircraft to provide flight crewmember training in a special purpose operation for which the aircraft is certificated is considered to be an operation for that special purpose.
(c) No person may operate a restricted category civil aircraft carrying persons or property for compensation or hire. For the purposes of this paragraph, a special purpose operation involving the carriage of persons or material necessary to accomplish that operation, such as crop dusting, seeding, spraying, and banner towing (including the carrying of required persons or material to the location of that operation), and operation for the purpose of providing flight crewmember training in a special purpose operation, are not considered to be the carriage of persons or property for compensation or hire.
(1) Is a flight crewmember;
(2) Is a flight crewmember trainee;
(3) Performs an essential function in connection with a special purpose operation for which the aircraft is certificated; or
(4) Is necessary to accomplish the work activity directly associated with that special purpose.
(e) Except when operating in accordance with the terms and conditions of a certificate of waiver or special operating limitations issued by the Administrator, no person may operate a restricted category civil aircraft within the United States -
(1) Over a densely populated area;
(2) In a congested airway; or
(3) Near a busy airport where passenger transport operations are conducted.
(g) No person may operate a small restricted-category civil airplane manufactured after July 18, 1978, unless an approved shoulder harness is installed for each front seat. The shoulder harness must be designed to protect each occupant from serious head injury when the occupant experiences the ultimate inertia forces specified in § 23.561(b)(2) of this chapter. The shoulder harness installation at each flight crewmember station must permit the crewmember, when seated and with the safety belt and shoulder harness fastened, to perform all functions necessary for flight operation. For purposes of this paragraph -
(2) A front seat is a seat located at a flight crewmember station or any seat located alongside such a seat.