Sec. 145.31 - Ratings.
The following ratings are issued under
(a) Airframe ratings. (1) Class
1: Composite construction of small aircraft.
(2) Class 2: Composite construction of
(3) Class 3: All-metal construction of
(4) Class 4: All-metal construction of
(b) Powerplant ratings. (1) Class
1: Reciprocating engines of 400 horsepower or less.
(2) Class 2: Reciprocating engines of
more than 400 horsepower.
(3) Class 3: Turbine engines.
(c) Propeller ratings. (1) Class
1: All fixed pitch and ground adjustable propellers of wood, metal, or
(2) Class 2: All other propellers, by
(d) Radio ratings. (1) Class 1:
Communication equipment: Any radio transmitting equipment or receiving
equipment, or both, used in aircraft to send or receive communications in
flight, regardless of carrier frequency or type of modulation used;
including auxiliary and related aircraft interphone systems, amplifier
systems, electrical or electronic inter-crew signaling devices, and
similar equipment; but not including equipment used for navigation of the
aircraft or as an aid to navigation, equipment for measuring altitude or
terrain clearance, other measuring equipment operated on radio or radar
principles, or mechanical, electrical, gyroscopic, or electronic
instruments that are a part of communications radio equipment.
(2) Class 2: Navigational equipment: Any
radio system used in aircraft for en route or approach navigation, except
equipment operated on radar or pulsed radio frequency principles, but not
including equipment for measuring altitude or terrain clearance or other
distance equipment operated on radar or pulsed radio frequency principles.
(3) Class 3: Radar equipment: Any
aircraft electronic system operated on radar or pulsed radio frequency
(e) Instrument ratings. (1) Class
1: Mechanical: Any diaphragm, bourdon tube, aneroid, optical, or
mechanically driven centrifugal instrument that is used on aircraft or to
operate aircraft, including tach- ometers, airspeed indicators, pressure
gauges drift sights, magnetic compasses, altimeters, or similar mechanical
(2) Class 2: Electrical: Any
self-synchronous and electrical indicating instruments and systems,
including remote indicating instruments, cylinder head temperature gauges,
or similar electrical instruments.
(3) Class 3: Gyroscopic: Any instrument
or system using gyroscopic principles and motivated by air pressure or
electrical energy, including automatic pilot control units, turn and bank
indicators, directional gyros, and their parts, and flux gate and gyrosyn
(4) Class 4: Electronic: Any instruments
whose operation depends on electron tubes, transistors, or similar devices
including capacitance type quantity gauges, system amplifiers, and engine
(f) Accessory ratings. (1) Class
1: Mechanical accessories that depend on friction, hydraulics, mechanical
linkage, or pneumatic pressure for operation, including aircraft wheel
brakes, mechanically driven pumps, carburetors, aircraft wheel assemblies,
shock absorber struts and hydraulic servo units.
(2) Class 2: Electrical accessories that
depend on electrical energy for their operation, and generators, including
starters, voltage regulators, electric motors, electrically driven fuel
pumps magnetos, or similar electrical accessories.
(3) Class 3: electronic accessories that
depend on the use of an electron tube transistor, or similar device,
including supercharger, temperature, air conditioning controls, or similar