Glossary

See height above airport.

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

See height above landing.

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

An electrical rectifier circuit that converts AC into pulsating DC. Only one alternation of each cycle is present in the output.

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

A hydrocarbon compound in which one or more hydrogen atoms have been replaced with atoms of one of the halogen elements such as fluorine, chlorine, or bromine.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A halogenated hydrocarbon fire-extinguishing agent used in many HRD fire-extinguishing systems for powerplant protection. The technical name for Halon 1211 is bromochlorodifluoromethane.

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

A halogenated hydrocarbon fire-extinguishing agent that is one of the best for extinguishing cabin and powerplant fires. It is highly effective and is the least toxic of the extinguishing agents available. The technical name for Halon 1301 is bromotrifluoromethane.

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

Scrapes, bends, and dents in an aircraft structure caused by careless handling.

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

Wood from a broadleaf tree that sheds its leaves each year.

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

See height above touchdown elevation.

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

Five aeronautical decision-making attitudes that may contribute to poor pilot judgment: anti-authority, impulsivity, invulnerability, machismo, and resignation. Hazardous Inflight Weather Advisory Service (HIWAS). An en route FSS service providing continuously updated automated of hazardous weather within 150 nautical miles of selected VORs, available only in the conterminous 48 states.

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

Pressure exerted by a column of fluid and created by the height of the column.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A special type of flight viewing screen that allows the pilot to watch the flight instruments and other data while looking through the windshield of the aircraft for other traffic, the approach lights, or the runway.

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

The direction in which the nose of the aircraft is pointing during flight.

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

A gyroscopic flight instrument that gives the pilot an indication of the heading of the aircraft.

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

Required to accomplish a conscious, rational thought process when making decisions. Good decision-making involves risk identification and assessment, information processing, and problem solving.

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

The total kinetic energy of the molecules of any substance.

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

A mechanical device that converts the chemical energy in a fuel into heat energy. The heat energy is then converted into mechanical energy and useful work.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A device used to exchange heat from one medium to another. Radiators, condensers, and evaporators are all examples of heat exchangers. Heat always moves from the object or medium having the greatest level of heat energy to a medium or object having a lower level.

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

The height of the MDA above the published airport elevation.

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

The height above a designated helicopter landing area used for helicopter instrument approach procedures.

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

The DA/DH or MDA above the highest runway elevation in the touchdown zone (first 3,000 feet of the runway).

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

The registered trade name of a special helical insert used to restore threads stripped from a bolt hole, or to reinforce the threads in an aluminum casting. The damaged threads are drilled out and new threads are cut with a special oversize tap. A coil of stainless steel wire, with a cross section in the shape of a diamond, is screwed into the hole and serves as the new threads. Heli-Coil inserts are also used to provide durable threads in soft metal castings. Some spark plug holes in aluminum alloy cylinder heads are fitted with Heli-Coil inserts to minimize the wear caused by repeated removal and installation of the spark plugs.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A spline that twists, or winds, around the periphery of a shaft. Helical splines are used to change linear motion into rotary motion of the shaft on which the splines are cut.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A spring wound in the form of a helix, or coil.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A screw-like, or spiral, curve.

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

The basic unit of inductance, symbolized with the letter H. An electric circuit has an inductance of one henry when current changing at the rate of one ampere per second induces a voltage of one volt into the circuit.

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

An organic compound, CH3(CH2)5CH3, that is used as the low reference fuel for rating the antidetonation characteristics of aviation gasoline.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

Generally used as a marking gauge in layout work. It should not be used for precision measurement.

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

A complete seal, especially against the escape or entry of air.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

One cycle per second.

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

High frequency.

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

Abbreviation for mercury, from the Latin hydrargyrum.

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

Indicates invisible edges or contours.

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

A turbofan engine whose bypass ratio is 4:1 or greater.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

An aircraft with an engine of more than 200 horsepower.

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

The second-stage compressor in a dual-spool gas turbine engine. The high pressure compressor is called the N2 compressor and is the one that is rotated by the starter for starting, and the one whose rpm is controlled by the fuel control.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

Pressure in a Teledyne- Continental fuel injector pump that is adjusted by the variable orifice.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

The inability of cells to effectively use oxygen. Plenty of oxygen is being transported to the cells that need it, but they are unable to use it.

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

See Hazardous Inflight Weather Advisory Service.

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

A predetermined maneuver that keeps aircraft within a specified airspace while awaiting further clearance from ATC.

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

A racetrack pattern, involving two turns and two legs, used to keep an aircraft within a prescribed airspace with respect to a geographic fix. A standard pattern uses right turns; nonstandard patterns use left turns.

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

An electrical relay that is closed by sending a pulse of current through the coil. It remains closed until the current flowing through its contacts is interrupted.

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

See amateur-built aircraft.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

Aircraft that are built by individuals as a hobby rather than by factories as commercial products. Homebuilt, or amateur-built, aircraft are not required to meet the stringent requirements imposed on the manufacture of FAA-certified aircraft.

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

Flying the aircraft on any heading required to keep the needle pointing to the 0° relative bearing position.

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

Scratching the surface of the cylinder wall with an abrasive to produce a series of grooves of microscopic depth and uniform pattern. The honed pattern holds oil to lubricate the cylinder walls.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A flight navigation instrument that combines the heading indicator with a CDI, in order to provide the pilot with better situational awareness of location with respect to the courseline.

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

A measure of power equal to 550 foot-pounds per second or 33,000 foot-pounds per minute and 746 Watts.

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

A process used to dimple, or indent, the hole into which a flush rivet is to be installed. Hot dimpling is done by clamping the metal between heating elements and forcing the dies through the holes in the softened metal. Hot dimpling prevents hard metal from cracking when it is dimpled.

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

The portion of a gas turbine engine that operates at a high temperature. The hot section includes the combustion, turbine, and exhaust sections.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

Occurs when the engine starts, but the exhaust gas temperature exceeds specified limits. This is usually caused by an excessively rich air-fuel mixture entering the combustion chamber.

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

A turbine engine lubricating system in which the oil cooler is located in the pressure subsystem. The oil is returned to the tank without being cooled.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A cutter used to shape blocks of Styrofoam. The wire is stretched tight between the arms of a frame and heated by electrical current. The hot wire melts its way through the foam.

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

High-rate-discharge.

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

A fire extinguisher that carries the extinguishing agent in a sealed sphere or cylinder. When the agent-discharged switch is closed, an ignited powder charge drives a cutter through a frangible disc which releases the agent. The entire contents of the container is emptied in much less than a second.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

Horizontal situation indicator.

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

The high-strength component inside a propeller that attaches the blades to the engine propeller shaft.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

See head-up display.

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

The study of how people interact with their environment. In the case of general aviation, it is the study of how pilot performance is influenced by such issues as the design of cockpits, the function of the organs of the body, the effects of emotions, and the interaction and communication with other participants in the aviation community, such as other crew members and air traffic control personnel.

Helicopter Flying Handbook, p. G-3

The amount of water vapor in the air.

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

Occurs when the engine starts normally, but the rpm. remains at some low value rather than increasing to the normal starting rpm. This is often the result of insufficient power to the starter, or the starter cutting off before the engine starts self-accelerating.

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

Movement of a blade with respect to the other blades in the plane of rotation, sometimes called leading or lagging.

Helicopter Flying Handbook, p. G-4

A gas turbine engine that has both centrifugal and axial-flow compressors.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A fine-wire spark plug that has a platinum center electrode and iridium ground electrodes.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

The component in a hydraulic system that converts hydraulic pressure into mechanical force. The two main types of hydraulic actuators are linear actuators (cylinders and pistons) and rotary actuators (hydraulic motors).

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

A type of flow control valve that allows a normal flow of fluid in the system but, if the flow rate is excessive, or if too much fluid flows for normal operation, the fuse will shut off all further flow.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

A condition in which oil drains into the lower cylinders of a reciprocating engine and leaks past the piston rings to fill the combustion chamber. If the oil is not removed before the engine is started, it can cause serious damage.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

A hydraulic actuator that converts fluid pressure into rotary motion. Hydraulic motors have an advantage in aircraft installations over electric motors, because they can operate in a stalled condition without the danger of a fire.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

A small, self-contained hydraulic system that consists of a reservoir, pump, selector valves, and relief valves. The power pack is removable from the aircraft as a unit to facilitate maintenance and service.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

The system of fluid power which transmits force through an incompressible fluid.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

An organic compound that contains only carbon and hydrogen. The vast majority of fossil fuels, such as gasoline and turbine-engine fuel, are hydrocarbons.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

Any device that combines fluid pressures with mechanical actions to achieve a desired result. In a hydromechanical fuel control used for a turbine engine, hydraulic servos are used in conjunction with the mechanical linkages.

Aviation Maintenance Technician Handbook — Powerplant, p. G-14

An instrument for determining the specific gravity of liquids.

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

A condition that exists when a high-speed airplane is landed on a water-covered runway. When the brakes are applied, the wheels lock up and the tires skid on the surface of the water in much the same way a water ski rides on the surface. Hydroplaning develops enough heat in a tire to ruin it.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

A pressure test used to determine the serviceability of high-pressure oxygen cylinders. The cylinders are filled with water and pressurized to 5⁄3 of their working pressure. Standard-weight cylinders (DOT 3AA) must by hydrostatically tested every five years, and lightweight cylinders (DOT 3HT) must be tested every three years.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

A type of hypoxia that is a result of oxygen deficiency in the blood, rather than a lack of inhaled oxygen. It can be caused by a variety of factors. Hypemic means “not enough blood.”

Pilot's Handbook of Aeronautical Knowledge, p. G-15

Electronic navigation systems that determine aircraft location by the time difference between reception of two signals. Signals from two stations at different locations will be received in the aircraft at different times. A line plotted between two stations along which the time difference is the same forms a hyperbola.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

Speed of greater than Mach 5 (5 times the speed of sound).

Aviation Maintenance Technician Handbook — Airframe, p. G-19

Occurs when an individual is experiencing emotional stress, fright, or pain, and the breathing rate and depth increase, although the carbon dioxide level in the blood is already at a reduced level. The result is an excessive loss of carbon dioxide from the body, which can lead to unconsciousness due to the respiratory system’s overriding mechanism to regain control of breathing.

Pilot's Handbook of Aeronautical Knowledge, p. G-15

The side of a right triangle that is opposite the right angle. The hypotenuse is the longest side of a right triangle.

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

A physiological condition in which a person is deprived of the needed oxygen. The effects of hypoxia normally disappear as soon as the person is able to breathe air containing sufficient oxygen.

Aviation Maintenance Technician Handbook — Airframe, p. G-19

This type of hypoxia is a result of insufficient oxygen available to the lungs. A decrease of oxygen molecules at sufficient pressure can lead to hypoxic hypoxia.

Pilot's Handbook of Aeronautical Knowledge, p. G-15