Glossary

Fretting or pulling out chunks of a surface by sliding contact with another surface or body.

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

General Aviation Manufacturers Association.

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

The basic gas turbine engine. It consists of the compressor, diffuser, combustor, and turbine. The gas generator is also called the core engine.

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

An internal combustion engine that burns its fuel in a constant-pressure cycle and uses the expansion of the air to drive a turbine which, in turn, rotates a compressor. Energy beyond that needed to rotate the compressor is used to produce torque or thrust.

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

A seal between two parts where there is no relative motion.

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

The distance between rows of rivets in a multirow seam. Gauge is also called transverse pitch.

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

Pressure referenced from the existing atmospheric pressure.

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

A constant-displacement fluid pump that contains two meshing large-tooth spur gears. Fluid is drawn into the pump as the teeth separate and is carried around the inside of the housing with teeth and is forced from the pump when the teeth come together.

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

A term used to describe the total field of aviation operation except the military and airlines.

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

While these documents are no longer published, they are still available at www.faa.gov. These are used to alert technicians of problems that have been found in specific models of aircraft, and reported on Malfunction and Defect Reports. Airworthiness Alerts suggest corrective action, but compliance with the suggestion is not mandatory.

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

A mechanical device that transforms mechanical energy into electrical energy by rotating a coil inside a magnetic field. As the conductors in the coil cut across the lines of magnetic flux, a voltage is generated that causes current to flow.

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

A set of heavy field windings in a generator connected in a series with the armature. The magnetic field produced by the series windings is used to change the characteristics of the generator.

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

A set of field windings in a generator connected in parallel with the armature. Varying the amount of current flowing in the shunt field windings controls the voltage output of the generator.

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

The distance a propeller would advance in one revolution if it were rotating in a solid.

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

The point in the standard atmosphere where the temperature stops dropping and becomes constant. This is the tropopause, or the dividing line between the troposphere and the stratosphere.

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

A form of constant-displacement gear pump. A gerotor pump uses an external-tooth spur gear that rides inside of and drives an internal-tooth rotor gear. There is one more tooth space inside the rotor than there are teeth on the drive gear. As the gears rotate, the volume of the space between two of the teeth on the inlet side of the pump increases, while the volume of the space between the two teeth on the opposite side of the pump decreases.

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

1,000,000,000 cycles per second.

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

A support that allows a gyroscope to remain in an upright condition when its base is tilted.

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

A type of support that allows an object, such as a gyroscope, to remain in an upright condition when its base is tilted.

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

An aircraft instrument system that uses a few cathode-ray-tube displays to replace a large number of mechanically actuated instruments.

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

Ice that forms when large drops of water strike a surface whose temperature is below freezing. Glaze ice is clear and heavy.

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

The portion of an ILS (Instrument Landing System) that provides the vertical path along which an aircraft descends on an instrument landing.

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

Part of the ILS that projects a radio beam upward at an angle of approximately 3° from the approach end of an instrument runway. The glideslope provides vertical guidance to aircraft on the final approach course for the aircraft to follow when making an ILS approach along the localizer path.

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

The minimum altitude of an intermediate approach segment prescribed for a precision approach that ensures obstacle clearance.

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

An instrument approach with lateral and vertical guidance with integrity limits (similar to barometric vertical navigation (BARO VNAV).

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

Satellite navigation system that provides autonomous geospatial positioning with global coverage. It allows small electronic receivers to determine their location (longitude, latitude, and altitude) to within a few meters using time signals transmitted along a line of sight by radio from satellites.

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

Navigation system that uses satellite rather than ground-based transmitters for location information.

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

See global landing system.

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

See global navigation satellite system.

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

Electronic circuitry in an ADF system that uses the output of a fixed loop antenna to sense the angle between a fixed reference, usually the nose of the aircraft, and the direction from which the radio signal is being received.

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

A control used to automatically change the pitch of a constant speed propeller to maintain a constant engine rpm as air loads vary in flight.

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

See global positioning system.

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

An authorization for pilots to use GPS avionics under IFR for flying designated existing nonprecision instrument approach procedures, with the exception of LOC, LDA, and SDF procedures.

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

Ground power unit. A service component used to supply electrical power and compressed air to an aircraft when it is operating on the ground.

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

See ground proximity warning system.

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

The basic unit of weight or mass in the metric system. One gram equals approximately 0.035 ounce.

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

A form of carbon. Structural graphite is used in composite structure because of its strength and stiffness.

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

The illusion of the cessation of a turn while still in a prolonged, coordinated, constant rate turn, which can lead a disoriented pilot to a loss of control of the aircraft.

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

See weight.

Helicopter Flying Handbook, p. G-3

The shortest distance across the surface of a sphere (the Earth) between two points on the surface.

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

The unshrunk condition of a polyester fabric as it is removed from the loom.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

The thrust produced by a turbojet or turbofan engine when the engine is static or not moving. The air is considered to have no inlet velocity, and the velocity of the gas leaving the engine is considered to be the acceleration factor.

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

The sum of the basic empty weight and useful load.

Helicopter Flying Handbook, p. G-3

The voltage reference point in an aircraft electrical system. Ground has zero electrical potential. Voltage values, both positive and negative, are measured from ground. In the United Kingdom, ground is spoken of as “earth.”

Aviation Maintenance Technician Handbook — Airframe, p. G-18

Non-movable metal trim tab on a control surface. Bent in one direction or another while on the ground to apply trim forces to the control surface.

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

An aircraft reciprocating engine with a built-in supercharger that boosts the sea-level rated horsepower of the engine.

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

The increased aerodynamic lift produced when an airplane or helicopter is flown nearer than half wing span or rotor span to the ground. This additional lift is caused by an effective increase in angle of attack without the accompanying increase in induced drag, which is caused by the deflection of the downwashed air.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

A service component used to supply electrical power to an aircraft when it is being operated on the ground.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

A system designed to determine an aircraft’s clearance above the Earth and provides limited predictability about aircraft position relative to rising terrain.

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

Selfexcited vibration occurring whenever the frequency of oscillation of the blades about the lead-lag axis of an articulated rotor becomes the same as the natural frequency of the fuselage.

Helicopter Flying Handbook, p. G-3

Speed over the ground, either closing speed to the station or waypoint, or speed over the ground in whatever direction the aircraft is going at the moment, depending upon the navigation system used.

Pilot's Handbook of Aeronautical Knowledge, p. G-14

The British name for a wrist pin, or piston pin. See wrist pin.

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

A highly explosive material made by treating cotton fibers with nitric and sulfuric acids. Guncotton is used in making the film base of nitrate dope.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

A small plate attached to two or more members of a truss structure. A gusset strengthens the truss.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

See ground proximity warning system.

Pilot's Handbook of Aeronautical Knowledge, p. G-14

The sensing device in an autopilot system. A gyroscope is a rapidly spinning wheel with its weight concentrated around its rim. Gyroscopes have two basic characteristics that make them useful in aircraft instruments: rigidity in space and precession. See rigidity in space and precession.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

The characteristic of a gyroscope that causes it to react to an applied force as though the force were applied at a point 90° in the direction of rotation from the actual point of application. The rotor of a helicopter acts in much the same way as a gyroscope and is affected by gyroscopic precession.

Aviation Maintenance Technician Handbook — Airframe, p. G-18

An inherent quality of rotating bodies, which causes an applied force to be manifested 90° in the direction of rotation from the point where the force is applied.

Helicopter Flying Handbook, p. G-3