The FAA uses various ways to classify or group machines operated or flown in the air. The most general grouping uses the term aircraft. This term is in 14 CFR 1.1 and means a device that is used or intended to be used for flight in the air.
Ultralight vehicle is another general term the FAA uses. This term is defined in 14 CFR 103. As the term implies, powered ultralight vehicles must weigh less than 254 pounds empty weight and unpowered ultralight vehicles must weigh less than 155 pounds. Rules for ultralight vehicles are significantly different from rules for aircraft; ultralight vehicle certification, registration, and operation rules are also contained in 14 CFR 103.
The FAA differentiates aircraft by their characteristics and physical properties. Key groupings defined in 14 CFR 1.1 include:
- Airplane—an engine-driven fixed-wing aircraft heavier than air, that is supported in flight by the dynamic reaction of the air against its wings.
- Glider—a heavier-than-air aircraft, that is supported in flight by the dynamic reaction of the air against its lifting surfaces and whose free flight does not depend principally on an engine.
- Lighter-than-air aircraft—an aircraft that can rise and remain suspended by using contained gas weighing less than the air that is displaced by the gas.
- Airship—an engine-driven lighter-than-air aircraft that can be steered.
- Balloon—a lighter-than-air aircraft that is not engine driven, and that sustains flight through the use of either gas buoyancy or an airborne heater.
- Powered-lift—a heavier-than-air aircraft capable of vertical takeoff, vertical landing, and low speed flight that depends principally on engine-driven lift devices or engine thrust for lift during these flight regimes and on non-rotating airfoil(s) for lift during horizontal flight.
- Powered parachute—a powered aircraft comprised of a flexible or semi-rigid wing connected to a fuselage so that the wing is not in position for flight until the aircraft is in motion. The fuselage of a powered parachute contains the aircraft engine, a seat for each occupant and Is attached to the aircraft’s landing gear.
- Rocket—an aircraft propelled by ejected expanding gases generated in the engine from self-contained propellants and not dependent on the intake of outside substances. It includes any part which becomes separated during the operation.
- Rotorcraft—a heavier-than-air aircraft that depends principally for its support in flight on the lift generated by one or more rotors.
- Gyroplane—a rotorcraft whose rotors are not engine-driven, except for Initial starting, but are made to rotate by action of the air when the rotorcraft Is moving; and whose means of propulsion, consisting usually of conventional propellers, is Independent of the rotor system.
- Helicopter—a rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors.
- Weight-shift-control—a powered aircraft with a framed pivoting wing and a fuselage controllable only in pitch and roll by the pilot’s ability to change the aircraft’s center of gravity with respect to the wing. Flight control of the aircraft depends on the wing’s ability to flexibly deform rather than the use of control surfaces.
Size and weight are other methods used in 14 CFR 1.1 to group aircraft:
- Large aircraft—an aircraft of more than 12,500 pounds, maximum certificated takeoff weight.
- Light-sport aircraft (LSA)—an aircraft, other than a helicopter or powered-lift that, since its original certification, has continued to meet the definition in 14 CFR 1.1. (LSA can include airplanes, airships, balloons, gliders, gyro planes, powered parachutes, and weight-shift-control.)
- Small Aircraft—aircraft of 12,500 pounds or less, maximum certificated takeoff weight.
We also use broad classifications of aircraft with respect to the certification of airmen or with respect to the certification of the aircraft themselves. See the next section, Pilot Certifications, for further discussion of certification. These definitions are in 14 CFR 1.1:
- As used with respect to the certification, ratings, privileges, and limitations of airmen, means a broad classification of aircraft. Examples include: airplane; rotorcraft; glider; and lighter-than-air; and
- As used with respect to the certification of aircraft, means a grouping of aircraft based upon intended use or operating limitations. Examples include: transport, normal, utility, acrobatic, limited, restricted, and provisional.
- As used with respect to the certification, ratings, privileges, and limitations of airmen, means a classification of aircraft within a category having similar operating characteristics. Examples Include: single engine; multiengine; land; water; gyroplane, helicopter, airship, and free balloon; and
- As used with respect to the certification of aircraft, means a broad grouping of aircraft having similar characteristics of propulsion, flight, or landing. Examples include: airplane, rotorcraft, gilder, balloon, landplane, and seaplane.
- As used with respect to the certification, ratings, privileges, and limitations of airmen, means a specific make and basic model of aircraft, Including modifications thereto that do not change its handling or flight characteristics. Examples include: 737-700, G-IV, and 1900; and
- As used with respect to the certification of aircraft, means those aircraft which are similar in design. Examples include: 737-700 and 737-700C; G-IV and G-IV-X; and 1900 and 1900C.
This system of definitions allows the FAA to group and regulate aircraft to provide for their safe operation.