18 U.S.C. § 31 — Definitions

(a) Definitions: This subsection defines ten terms used in this chapter. (1) Aircraft: An "aircraft" is any craft — civilian, military, or public — that is built, used, or meant to fly or travel through the air. (2) Aviation quality: A part of an aircraft or space vehicle has "aviation quality" if it was made, built, produced, fixed, overhauled, rebuilt, reconditioned, or restored according to the legal standards (including regulations) that apply to it. (3) Destructive substance: A "destructive substance" is an explosive, flammable material, an infernal machine (a hidden explosive device), or any other chemical, mechanical, or radioactive device or material that can combust, contaminate, corrode, or explode. (4) In flight: An aircraft is "in flight" from the moment all its outside doors close after people board, until the moment a door opens again for people to get off. If the aircraft makes a forced landing, it stays "in flight" until the proper authorities take charge of the aircraft, the people, and the property on board. (5) In service: An aircraft is "in service" starting whenever ground crew or the flight crew begin preparing it for a specific flight, and it stays "in service" until 24 hours after it lands. This period always includes the whole time the aircraft is actually flying. (6) Motor vehicle: A "motor vehicle" is any kind of carriage or device that's pulled or powered by machinery, and that's used commercially on highways to carry passengers, passengers and property together, or property and cargo alone. (7) Part: A "part" is a frame, assembly, component, appliance, engine, propeller, material, spare part, piece, section, or any related equipment that's built in or used alongside these things. (8) Space vehicle: A "space vehicle" is a device built by people — whether or not anyone is on board — that's designed to operate beyond Earth's atmosphere. (9) State: A "State" means any U.S. state, the District of Columbia, or any U.S. commonwealth, territory, or possession. (10) Used for commercial purposes: This phrase means carrying people or property for any fare, fee, rate, charge, or other payment, or doing so as part of any business or other profit-seeking activity, whether directly or indirectly. (b) Terms Defined in Other Law: This chapter also uses several terms it doesn't define itself. Instead, "aircraft engine," "air navigation facility," "appliance," "civil aircraft," "foreign air commerce," "interstate air commerce," "landing area," "overseas air commerce," "propeller," "spare part," and "special aircraft jurisdiction of the United States" all carry the meanings given to them in sections 40102(a) and 46501 of title 49.