Glossary

See area forecast.

Pilot's Handbook of Aeronautical Knowledge, p. G-11

This form must be completed when a major repair or alteration is accomplished.

Aviation Maintenance Technician Handbook — General, p. G-5

The flat surface of a propeller that strikes the air as the propeller rotates. The face of a propeller corresponds to the bottom of an airplane wing.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

Full-authority digital electronic control. A digital electronic fuel control for a gas turbine engine that is functioning during all engine operations, hence full authority. It includes the EEC (see EEC) and functions with the flight management computer. FADEC schedules the fuel to the nozzles in such a way that prevents overshooting power changes and over-temperature conditions. FADEC furnishes information to the EICAS (engine indication and crew alerting system).

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

The decrease in the amount of braking action that occurs with some types of brakes that are applied for a long period of time. True fading occurs with overheated drum-type brakes. As the drum is heated, it expands in a bell-mouthed fashion. This decreases the amount of drum in contact with the brake shoes and decreases the braking action. A condition similar to brake fading occurs when there is an internal leak in the brake master cylinder. The brakes are applied, but as the pedal is held down, fluid leaks past the piston, and the brakes slowly release.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

See final approach fix.

Pilot's Handbook of Aeronautical Knowledge, p. G-11

A part of a structure whose primary purpose is to produce a smooth surface or a smooth junction where two surfaces join.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

A plastic or wooden guide used to prevent a steel control cable rubbing against an aircraft structure.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

Inaccurate visual information for aligning the aircraft, caused by various natural and geometric formations that disorient the pilot from the actual horizon.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

The ratio of the fan-discharge pressure to the fan inlet pressure.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

Federal Communications Commission.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

See flight director indicator.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Rotation of a helicopter rotor blade about its pitch-change axis.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

The action that changes the pitch angle of the rotor blades by rotating them around their feathering (spanwise) axis.

Helicopter Flying Handbook, p. G-3

The axis about which the pitch angle of a rotor blade is varied. Sometimes referred to as the spanwise axis.

Helicopter Flying Handbook, p. G-3

A controllable-pitch propeller whose blades can be moved into a high pitch angle of approximately 90º. Feathering the propeller of an inoperative engine prevents it from wind-milling and greatly decreases drag.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

Class E airspace areas that extend upward from 1,200 feet to, but not including, 18,000 feet MSL, unless otherwise specified.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

The transmittal of forces, which are initiated by aerodynamic action on rotor blades, to the cockpit controls.

Helicopter Flying Handbook, p. G-3

Used by ATC to direct aircraft to intervening fixes between the en route structure and the initial approach fix.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

A type of measuring tool consisting of strips of precision-ground steel of accurately measured thickness. Feeler gages are used to measure the distance between close-fitting parts, such as the clearances of a mechanical system or the distance by which moving contacts are separated.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

Any metal that contains iron and has magnetic characteristics.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

Metals having iron as their principal constituent.

Aviation Maintenance Technician Handbook — General, p. G-5

Friction horsepower. The amount of horsepower used to turn the crankshaft, pistons, gears, and accessories in a reciprocating engine and to compress the air inside the cylinders.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

The technique of transmitting light or images through long, thin, flexible fibers of plastic or glass. Bundles of fibers are used to transmit complete images.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

A form of a self-locking nut that has a fiber insert crimped into a recess above the threads. The hole in the insert is slightly smaller than the minor diameter of the threads. When the nut is screwed down over the bolt threads, the opposition caused by the fiber insert produces a force that prevents vibration loosening the nut.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

A hand-held cutting tool used to remove a small amount of metal with each stroke.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

Threads in a piece of fabric that run across the width of the fabric, interweaving with the warp threads. Fill threads are often called woof, or weft, threads.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

A fairing used to give shape but not strength to an object. A fillet produces a smooth junction where two surfaces meet.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

Part of an instrument approach procedure in which alignment and descent for landing are accomplished.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Another name for surface tape. See surface tape.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

The handle in an aircraft flight deck that is pulled at the first indication of an engine fire. Pulling this handle removes the generator from the electrical system, shuts off the fuel and hydraulic fluid to the engine, and closes the compressor bleed air valve. The fire extinguisher agent discharge switch is uncovered, but it is not automatically closed.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

A covering of fire-resistant fabric used to protect flexible fluid lines that are routed through areas subject to high temperature.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

A portion of an aircraft designated by the manufacturer to require fire-detection and/or fire-extinguishing equipment and a high degree of inherent fire resistance.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

A type of splice used in a welded tubular structure in which the end of the tube whose inside diameter is the same as the outside diameter of the tube being spliced is cut in the shape of a V, or a fishmouth, and is slipped over the smaller tube welded. A fishmouth splice has more weld area than a butt splice and allows the stresses from one tube to transfer into the other tube gradually.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

An attachment device that is used to connect components to an aircraft structure.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

Staring at a single instrument, thereby interrupting the cross-check process.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

A fire-extinguishing system installed in an aircraft.

Aviation Maintenance Technician Handbook — Airframe, p. G-15

Propellers with fixed blade angles. Fixed-pitch propellers are designed as climb propellers, cruise propellers, or standard propellers.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

A fixed, nozzle shaped opening near the leading edge of a wing that ducts air onto the top surface of the wing. Its purpose is to increase lift at higher angles of attack.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

See flight level.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Small-diameter metal tubes that connect can-type combustors in a turbine engine to carry the ignition flame to all of the combustion chambers. The British call combustion liners flame tubes.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

A condition in the operation of a gas turbine engine in which the fire in the engine unintentionally goes out.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A secondary control on an airplane wing that changes its camber to increase both its lift and its drag.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A valve in the flap system of an airplane that prevents the flaps being lowered at an airspeed which could cause structural damage. If the pilot tries to extend the flaps when the airspeed is too high, the opposition caused by the air flow will open the overload valve and return the fluid to the reservoir.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

The vertical movement of a blade about a flapping hinge.

Helicopter Flying Handbook, p. G-3

The hinge that permits the rotor blade to flap and thus balance the lift generated by the advancing and retreating blades.

Helicopter Flying Handbook, p. G-3

Hinged portion of the trailing edge between the ailerons and fuselage. In some aircraft ailerons and flaps are interconnected to produce full-span “flaperons.” In either case, flaps change the lift and drag on the wing.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

A maneuver accomplished prior to landing to slow a helicopter.

Helicopter Flying Handbook, p. G-3

The temperature to which a material must be raised for it to ignite, but not continue to burn, when a flame is passed above it.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A maintenance procedure for a DC generator that restores residual magnetism to the field frame, A pulse of current from a battery is sent through the field coils in the direction in which current normally flows. The magnetic field produced by this current magnetizes the steel frame of the generator.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

An ignition system malfunction in which the high voltage in the magneto distributor jumps to the wrong terminal. Flashover causes the wrong spark plug to fire. This reduces the engine power and produces vibration and excessive heat.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

The pattern for a sheet metal part that has the material used for each flat surface, and for all of the bends, marked out with bend-tangent lines drawn between the flats and bend allowances.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A turboprop engine whose allowable output power is less than the engine is physically capable of producing.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

An average weight accepted by the FAA for aircraft of identical make and model that have the same equipment installed. When a fleet weight control program is in effect, the fleet weight of the aircraft can be used rather than requiring every individual aircraft to be weighed.

Aircraft Weight and Balance Handbook, p. G-3

Adjusting the aircraft control surfaces (including flaps and landing gear) in a manner that will achieve a specified attitude.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

The component in an autopilot system that allows the pilot to maneuver the aircraft manually when the autopilot is engaged.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

One of the major components of a flight director system, it provides steering commands that the pilot (or the autopilot, if coupled) follows.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Provides pilot and crew with highly accurate and automatic long-range navigation capability, blending available inputs from long- and short-range sensors.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

The line, course, or track along which an aircraft is flying or is intended to be flown.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Basic maneuvers, flown by reference to the instruments rather than outside visual cues, for the purpose of practicing basic attitude flying. The patterns simulate maneuvers encountered on instrument flights such as holding patterns, procedure turns, and approaches.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Paper strips containing instrument flight information, used by ATC when processing flight plans.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

A fuel metering device that uses a float-actuated needle valve to maintain fuel level slightly below the edge of the discharge nozzle.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

Pulverized wood or cotton fibers mixed with an adhesive. Flock, attached to a wire screen, acts as an effective induction air filter for small reciprocating engines.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

The maximum weight the floor can sustain per square inch/foot as provided by the manufacturer.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

The valve in an RSA fuel injection system that divides the fuel from the fuel control unit and distributes it to all of the cylinders. It compares with the manifold valve in a Teledyne-Continental fuel injection system.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

A form of material whose molecules are able to flow past one another without destroying the material. Gases and liquids are both fluids.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

The transmission of force by the movement of a fluid. The most familiar examples of fluid power systems are hydraulic and pneumatic systems.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

Rapid and uncontrolled oscillation of a flight control surface on an aircraft that is caused by a dynamically unbalanced condition.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A method of control used by some modern aircraft in which control movement or pressures exerted by the pilot are directed into a digital computer where they are input into a program tailored to the flight characteristics of the aircraft. The computer output signal is sent to actuators at the control surfaces to move them the optimum amount for the desired maneuver.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

An airplane whose fuselage is built in the form of a boat hull to allow it to land and takeoff from water. In the past, flying boats were a popular form of large airplane.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A type of heavier-than-air aircraft that has no fuselage or separate tail surfaces. The engines and useful load are carried inside the wing, and movable control surfaces on the trailing edge provide both pitch and roll control.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

Flight Management Computer.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

See flight management system.

Pilot's Handbook of Aeronautical Knowledge, p. G-12

Foreign object damage. Damage to components in the gas path of a turbine engine, caused by ingested objects. Debris from the runway or ramp cause FOD on the ground. Ice and birds cause most in-flight FOD.

Aviation Maintenance Technician Handbook — Powerplant, p. G-12

Cloud consisting of numerous minute water droplets and based at the surface; droplets are small enough to be suspended in the earth’s atmosphere indefinitely. (Unlike drizzle, it does not fall to the surface. Fog differs from a cloud only in that a cloud is not based at the surface, and is distinguished from haze by its wetness and gray color.)

Pilot's Handbook of Aeronautical Knowledge, p. G-12

A measure of work accomplished when a force of 1 pound moves an object a distance of 1 foot.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

The intensity of an impetus, or the intensity of an input.

Aviation Maintenance Technician Handbook — General, p. G-5

Welding in which the torch is pointed in the direction the weld is progressing.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

Any damage caused by any loose object to aircraft, personnel, or equipment. These loose objects can be anything from broken runway concrete to shop towels and safety wire.

Aviation Maintenance Technician Handbook — General, p. G-5

Parasite drag caused by the form of the object passing through the air.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

An aircraft structural member used to give a fuselage its shape.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A condition of operation of a semiconductor device such as a diode or transistor in which a positive voltage is connected to the P-type material and a negative voltage to the N-type material.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A constant-volume cycle of energy transformation that has separate strokes for intake, compression, power, and exhaust.

Aviation Maintenance Technician Handbook — Powerplant, p. G-13

Freezing point depressant.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A number written in the form N⁄D in which N is the numerator and D is the denominator. For example, 5⁄16 is a fraction.

Aviation Maintenance Technician Handbook — General, p. G-5

A method of separating the various components from a physical mixture of liquids. The material to be separated is put into a container and its temperature is increased. The components having the lowest boiling points boil off first and are condensed. Then, as the temperature is further raised, other components are removed. Kerosene, gasoline, and other petroleum products are obtained by fractional distillation of crude oil.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

Breakable, or easily broken.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

A turboshaft engine with no physical connection between the compressor and power output shaft.

Helicopter Flying Handbook, p. G-3

A gas turbine engine with a turbine stage on a shaft independent of the shaft used to drive the compressor. Free turbines are used to drive the propeller reduction gear in a turboprop engine and the rotor transmission in a helicopter.

Aviation Maintenance Technician Handbook — Powerplant, p. G-13

A component of the transmission or power train that automatically disconnects the main rotor from the engine when the engine stops or slows below the equivalent rotor rpm.

Helicopter Flying Handbook, p. G-3

The temperature at which solids, such as wax crystals, separate from a hydrocarbon fuel as it is cooled.

Aviation Maintenance Technician Handbook — Powerplant, p. G-13

The registered trade name for a refrigerant used in a vapor-cycle air conditioning system.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

The number of cycles (on/off) completed per unit of time. Usually expressed in Hertz.

Aviation Maintenance Technician Handbook — General, p. G-5

Occurs when two mating surfaces, normally at rest with respect to one another, are subject to slight relative motion.

Aviation Maintenance Technician Handbook — General, p. G-5

The opposition to movement between objects.

Aviation Maintenance Technician Handbook — General, p. G-5

An aileron with its hinge line set back from the leading edge so that when it is deflected upward, part of the leading edge projects below the wing and produces parasite drag to help overcome adverse yaw.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

Aileron having the nose portion projecting ahead of the hinge line. When the trailing edge of the aileron moves up, the nose projects below the wing’s lower surface and produces some parasite drag, decreasing the amount of adverse yaw.

Pilot's Handbook of Aeronautical Knowledge, p. G-13

The boundary between two different air masses.

Pilot's Handbook of Aeronautical Knowledge, p. G-13

Ice crystal deposits formed by sublimation when the temperature and dew point are below freezing.

Aviation Maintenance Technician Handbook — Airframe, p. G-17

A device in the fuel line between the engine-driven fuel pump and the carburetor that measures the rate of flow of the fuel. It converts this flow rate into an electrical signal and sends it to an indicator in the instrument panel.

Aviation Maintenance Technician Handbook — Airframe, p. G-17

The rating system used for aviation gasoline. It rates fuel according to its antidetonation characteristics.

Aviation Maintenance Technician Handbook — General, p. G-5

A system installed in most large aircraft that allows the flight crew to jettison, or dump, fuel to lower the gross weight of the aircraft to its allowable landing weight. Boost pumps in the fuel tanks move the fuel from the tank into a fuel manifold. From the fuel manifold, it flows away from the aircraft through dump chutes is each wing tip. The fuel jettison system must be so designed and constructed that it is free from fire hazards.

Aviation Maintenance Technician Handbook — Airframe, p. G-17

The expendable part of the load of the airplane. It includes only usable fuel, not fuel required to fill the lines or that which remains trapped in the tank sumps.

Pilot's Handbook of Aeronautical Knowledge, p. G-13

A fuel quantity indicator that gives the total amount of fuel remaining on board the aircraft on one instrument. The totalizer adds the quantities of fuel in all of the tanks.

Aviation Maintenance Technician Handbook — Airframe, p. G-17

The point about which a lever balances.

Aircraft Weight and Balance Handbook, p. G-3

Not thinned.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

The position of a magnet in a magneto when its poles are aligned with the pole shoes and the maximum amount of magnetic flux is flowing through the magnetic circuit.

Aviation Maintenance Technician Handbook — Powerplant, p. G-13

A helicopter rotor whose blades are attached to the hub in such a way that they are free to flap, drag, and feather. See each of these terms.

Aviation Maintenance Technician Handbook — Airframe, p. G-16

See articulated rotor system.

Helicopter Flying Handbook, p. G-3

Pilot skills of instrument cross-check, instrument interpretation, and aircraft control.

Pilot's Handbook of Aeronautical Knowledge, p. G-13

Any of several types of plant life that include yeasts, molds, and mildew.

Aviation Maintenance Technician Handbook — Airframe, p. G-17

A protective device containing a special wire that melts when current exceeds the rated value for a definite period.

Aviation Maintenance Technician Handbook — General, p. G-5

The section of the airplane that consists of the cabin and/or cockpit, containing seats for the occupants and the controls for the airplane.

Pilot's Handbook of Aeronautical Knowledge, p. G-13

Reference locations, usually given in inches, used to determine forward and aft positions on an aircraft. FS − 0 is the datum.

Aviation Maintenance Technician Handbook — General, p. G-5

Plugs in the wheels of high-performance airplanes that use tubeless tires. The centers of the plugs are filled with a metal that melts at a relatively low temperature. If a takeoff is aborted and the pilot uses the brakes excessively, the heat transferred into the wheel will melt the center of the fusible plugs and allow the air to escape from the tire before it builds up enough pressure to cause an explosion.

Aviation Maintenance Technician Handbook — Airframe, p. G-17