Alpha
Bismillah
Charlie Delta
Echo
Foxtrot
Golf
Hotel
insaallah Juliett
Kilo
Lima
Mike
November
Oscar
Piaggio Quebec Romeo
Sierra Turks Uniform
Victory Water X-ray
Yankee Zulu Main Page
N3
N3
The speed of high pressure compressor in a triple-spool turbine engine.nacelle The streamlined enclosure on the wing or fuselage of an aircraft that houses the engine.
NAND gate A not and logic device, which will not have a voltage at its output only when a voltage appears at all of the inputs. Opposite to an and gate.
nano One billionth (0.000000001) of a unit.
nanovoltmeter A sensitive voltmeter that measures voltages as low as one nanovolt.
nap The short fiber ends that protrude from the surface of a fabric. When the fabric is doped, these fibers become stiff and must be sanded off.
naphtha A volatile and flammable hydrocarbon liquid used chiefly as a solvent or cleaning agent.
narrowing grinding The removable part of the valve seat s top edge in the cylinder of a reciprocating engine.
NAS drawings and specifications Dimensional and material standards for aircraft fasteners developed by the National Aircraft Standards (NAS) Committee. All drawings and specifications are prefixed by NAS.
NAS stage A The enroute ATC system s radar, computers and computer programs, controller plan view displays (PVDs/Radar Scopes), input/output devices, and the related communications equipment that are integrated to form the heart of the automated IFR air traffic control system. This equipment performs Flight Data Processing (FDP) and Radar Data Processing (RDP). It interfaces with automated terminal systems and is used in the control of enroute IFR aircraft.
National Airspace System The common network of United States airspace, air navigation facilities, equipment and services, airports or landing areas, aeronautical charts, information and services, rules, regulations and procedures, technical information, and manpower and material. Included are system components shared jointly with the military.
National Beacon Code Allocation Plan (NBCAP) airspace Airspace over United States territory located within the North American continent between Canada and Mexico, including adjacent territorial waters outward to about boundaries of oceanic control areas (CTA)/Flight Information Regions (FIR).
National Flight Data Center A facility in Washington D.C., established by FAA to operate a central aeronautical information service for the collection, validation, and dissemination of aeronautical data in support of the activities of government, industry, and the aviation community. The information is published in the National Flight Data Digest.
National Flight Data Digest A daily (except weekends and Federal holidays) publication of flight information appropriate to aeronautical charts, aeronautical publications, Notices to Airmen, or other media serving the purpose of providing operational flight data essential to safe and efficient aircraft operations.
national route program (NRP) The NRP is a set of rules and procedures designed to increase the flexibility of user flightplanning within published guidelines.
national search and rescue plan An interagency agreement that provides for the effective utilization of all available facilities in all types of search and rescue missions.
natural aging The aging of solution, heat-treated aluminum alloy material. It is allowed to harden at room temperature following heat treatment.
natural numbers Positive integers such as 1, 2, 8, and 9. Negative numbers, zero and fractions are NOT natural numbers.
naturally aspirated engine A reciprocating aircraft engine that is not supercharged, but whose induction air is forced into the cylinders by atmospheric pressure only.
nautical mile A measure of distance used primarily in navigation. It is equal to 6,076 feet and is one minute of latitude at the equator.
nautical twilight The periods before sunrise and after sunset when the sun is not more than 12 below the horizon.
NAVAID Any visual or electronic device, airborne or on the surface, that provides point-to-point guidance information, or position data, to aircraft in flight. NAVAIDs include VORs, ILSs, and DMEs.
NAVAID classes VOR, VORTAC, and TACAN aids are classed according to their operational use. The three classes of NAVAIDs are:
a. T Terminal
b. L Low altitude
c. H High altitude
NOTE: The normal service range for T, L, and H class aids is found in the AIM. Certain operational requirements make it necessary to use some of these aids at greater service ranges than specified. Extended range is made possible through flight inspection determinations. Some aids also have lesser service range due to location, terrain, frequency protection, etc. Restrictions to service range are listed in the Airport/Facility Directory.
navigable airspace Airspace at and above the minimum flight altitudes prescribed in the FARs including airspace needed for safe takeoff and landing.
navigate To move between sites on the Internet. Often done by means of links or connections between sites.
navigation lights Lights on an aircraft consisting of a red light on the left wing, a green light on the right wing, and a white light on the tail. FARs require that these lights be displayed in flight during the hours of darkness.
navigational aid (NAVAID) Any visual or electronic device, airborne or on the surface, that provides point-to-point guidance information, or position data, to aircraft in flight. NAVAIDs include VORs, ILSs, and DMEs.
NBCAP (National Beacon Code Allocation Plan) airspace Airspace over United States territory located within the North American continent between Canada and Mexico, including adjacent territorial waters outward to about boundaries of oceanic control areas (CTA)/Flight Information Regions (FIR).
N-channel field effect transistor (FET) A device with a conducting channel of N-type material that is on a P-type substrate. It can conduct in either direction, thus it can pass AC. One end of the channel is called a drain and the other a source. These are brought out to pins for connection into an external circuit. A third connection is to the gate. The gate can be P-type material. When the gate is made negative in respect to the channel, a depletion area is formed that reduces the channel current and allows control of it. The input impedance of any FET is very high.
neck 1. A portion of a fastener s body near the head that performs a definite function such as preventing rotation, etc. 2. A reduced diameter of a portion of a fastener s shank required for design or manufacturing reasons.
needle and ball indicator A flight instrument consisting of a rate gyro that indicates the rate of yaw and a curved glass clinometer that indicates the relationship between gravity and centrifugal force. It indicates the relationship between angle of bank and rate of yaw. Also referred to as a turn and slip indicator.
needle bearings An anti-friction bearing made of hardened steel. The bearing consists of a series of small diameter rollers that ride between two hardened and polished steel races. One race is pressed into the housing, and the other race is pressed onto the rotating shaft.
needle valve A tapered end fluid control needle valve that fits into a seat or recess to control or restrict a flow of fluid through an orifice.
negative 1. A condition in which there is an excess of electrons. 2. An accepted name for the terminal of a battery or power source from which the electrons flow. 3. During communications, this indicates: No, Permission not granted, or That is not correct.
negative acceleration Deceleration; slowing down.
negative angle of attack A flight condition where the angle of attack formed between the relative wind and the chord line of the airfoil is formed with the relative wind being the top leg in relation to the chord line and the so-called top surface of the aircraft. An aircraft in inverted, level flight would have a negative angle of attack.
negative battery terminal The terminal of a battery from which the electrons leave and enter the circuit.
negative buoyancy The tendency of an object, when placed in a fluid, to sink because it is heavier than the fluid it displaces.
negative condition One in which there is an excess of electrons.
negative contact Used by pilots to inform ATC one of two things. Either that previously issued traffic is not in sight or that they were unable to contact ATC on a particular frequency. The first instance might be followed by the pilot s request for the controller to provide assistance in avoiding the traffic.
negative dihedral A downward inclination of a wing or other surface. It is the downward angle that is formed between the wings and the lateral axis of the airplane.
negative electrical charge An unbalanced electrical condition caused by an atom having more electrons than protons.
negative electrical condition A condition in which there are more negative charges than there are positive charges.
negative electrical resistance A decrease in current through a device when there is an increase in voltage.
negative feedback Information or a signal that is fed back into a circuit or device that tends to cause a decrease in the output.
negative ion An atom that has more electrons than protons spinning around its nucleus.
negative moment In aircraft weight and balance calculations, a moment resulting from an arm being forward of the datum.
negative pressure Pressure that is less than atmospheric pressure.
negative pressure relief valve A valve in an aircraft pressurization system that prevents the outside air pressure from becoming greater than the pressure inside the cabin
negative resistance A condition in which the normal direct relationship between voltage and current is reversed.
negative stagger The placement of the wings of a biplane in which the leading edge of the lower wing is ahead of the leading edge of the upper wing.
negative static stability A condition in which an object disturbed from a condition of rest will tend to move further away from its condition of rest.
negative temperature coefficient A condition where a conductor or device decreases in resistance as the temperature increases.
negative thrust The thrust produced when a propeller is moved into the beta range.
negative torque system (NTS) A system in a turboprop engine that prevents the engine from being overdriven by the propeller. The NTS increases the blade angle when the propellers try to overdrive the engine.
negative transfer of learning Students interpret new things in terms of what they already know. Some degree of transfer is involved in all learning. Previous learning interferes with students understanding of the current task.
negative vacuum relief valve A relief valve used on pressurized aircraft that opens when outside air pressure is greater than cabin pressure.
negative value A value less than zero.
neon A gaseous element with a symbol of Ne and an atomic number of 10.
neon bulb A bulb that glows when neon vapor atoms are excited by an electric arc.
neoprene An oil-resistant synthetic rubber made by polymerizing chloroprene. Used in items such as seals and locknuts.
net thrust (Fn) The effective thrust developed by a jet engine during flight, taking into consideration the initial momentum of the air mass prior to entering the engine.
neutral 1. The condition in which a gear, lever, or other mechanism is not engaged. 2. An electrical condition that is neither positive nor negative.
neutral axis An imaginary line through the length of a loaded beam where the forces of compression and tension are neutral.
neutral conductor The conductor of a 3-phase circuit or a single-phase three wire circuit that is of a ground potential. The potential between the neutral and each of the other conductors is equal in magnitude and phase.
neutral flame A flame used in oxyacetylene welding that is neither carburizing nor oxidizing and that uses the correct ratio of acetylene gas and oxygen.
neutral line In sheet metal bending, the line near the middle of the sheet that is unaffected by either compression on the inside of the curve, or by stretching on the outside of the curve.
neutral plane An imaginary line drawn perpendicular to the resultant flux in a generator. For arcless commutation, the neutral plane should lie directly over the plane of the brushes.
neutral position The position of the rotating magnet of a magneto between the pole shoes. In the neutral position, no lines of flux flow in the magneto frame.
neutral stability A system is characterized by neutral stability if, when displaced, it accelerates neither toward nor away from its original position. The atmosphere displays neutral stability when lapse rate is equal to the dry adiabatic lapse rate.
neutral static stability The condition of an object in which, when once disturbed from a condition of rest, it has neither the tendency to return to a condition of rest nor to depart further from it. It continues in equilibrium in the direction of disturbance.
neutralize To make balanced or inert by combining equal positive and negative quantities.
neutron An uncharged particle in the nucleus of an atom. Its mass is essentially equal to that of a proton.
never exceed speed The speed beyond which an aircraft should never be operated.
newton The unit of force in the meter-kilogram-second system equal to the force required to impart an acceleration of one meter per second squared to a mass of one kilogram.
Newton s first law of motion The law of physics that describes inertia. A body at rest tends to remain at rest and a body in motion tends to continue to move at constant speed, along a straight line, unless it is acted upon by an external force.
Newton s second law The law of physics that states: The acceleration produced in a mass by the addition of a given force is directly proportional to the force, and inversely proportional to the mass.
Newton s second law of motion The greater the force acting on an object, the greater the acceleration. And the greater the mass, the less the object will accelerate.
Newton s third law The law of physics that states: For every action, there is an equal and opposite reaction.
Newton s third law of motion The law of physics that describes action and reaction. For every action, there is an equal and opposite reaction.
nibble To take small bites or quantity.
nibbler A sheet metal cutting tool that cuts the metal by a series of small nibbles or bites.
nichrome An alloy of nickel and chromium. It is used for making precision wire-wound resistors.
nick A sharp-sided gouge or depression with a V-shaped bottom that is generally the result of careless handling.
nickel A silver-white, hard, malleable, metallic chemical element with a symbol of Ni and an atomic number of 28. Used for plating because of its high resistance to oxidation.
nickel silver A metal alloy of copper, zinc, and nickel.
nickel-cadmium battery (Nicad) A battery made up of alkaline secondary cells. The positive plates are nickel hydroxide, the negative plates are cadmium hydroxide, and potassium hydroxide is used as the electrolyte.
night The time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time.
night [ICAO] The hours between the end of evening civil twilight and the beginning of morning civil twilight or such other period between sunset and sunrise as can be specified by the appropriate authority.
NOTE: Civil twilight ends in the evening when the center of the sun s disk is 6 degrees below the horizon and begins in the morning when the center of the sun s disk is 6 degrees below the horizon.
nimbostratus A dark gray cloud layer that produces rain or snow.
Nimonic alloy A nickel-chromium alloy used for sheet-metal fabrications in gas-turbine engines.
nipple pipe fitting A short piece of pipe fitting threaded on both ends.
nitrate A salt or ester of nitric acid (HNO3). Used in some dopes to protect fabric-covered aircraft.
nitrate dope A finish for aircraft fabric, consisting of a film base of cellulose fibers dissolved in nitric acid with the necessary plasticizers, solvents, and thinners.
nitric acid A colorless or yellowish flowing, suffocating, caustic, corrosive, water-soluble liquid (HN03) with powerful oxidizing properties.
nitriding A case hardening in which a steel part is heated in an atmosphere of ammonia (NH3.) The ammonia breaks down, freeing the nitrogen to combine with aluminum in the steel to form an extremely hard abrasive-resistant aluminum nitride surface. Cylinder walls and crankshaft journals can be nitrided.
nitrite A salt or ester of nitrous acid (HNO2).
nitrogen A colorless, tasteless, odorless, gaseous element forming nearly 4/5 of the Earth s atmosphere.
no gyro approach A radar approach/vector provided in case of a malfunctioning gyro-compass or directional gyro. Instead of providing the pilot with headings to be flown, the controller observes the radar track and issues control instructions turn right/left or stop turn as appropriate.
no gyro vector See no gyro approach.
no procedure turn (NOPT) No procedure turn is required nor authorized.
no transgression zone (NTZ) The NTZ is a 2,000 foot wide zone, located equidistant between parallel runway final approach courses in which flight is not allowed.
noble Chemically inert or inactive, especially toward oxygen.
noble gas An inert gas such as neon, argon, krypton, and xenon.
nocturnal inversion A surface-based stable layer that occurs due to nighttime radiational cooling.
nodal system A vibration dampening system used by Bell Helicopter to reduce main rotor vibration.
noise 1. A general term for any loud or unusual sound that is annoying or excessive. 2. Undesired signals within an electronic circuit.
noise suppressor A device installed in the tailpipe of a turbojet engine to slow the mixing of the exhaust gases with the surrounding air, thus decreasing the intensity of the sound.
no-load current The electrical current draw of a device when the device is not under load.
Nomex
Trademark of DuPont. A nylon paper treated material that is made into a honeycomb core material.nominal rating The stated value of a quantity or component, which might not be the actual value measured.
nominal resistance of a thermistor The true resistance of a thermistor at a particular reference temperature. Most manufacturers use 20 C as the reference temperature.
nominal size The designation used for the purpose of general identification.
nominal value A stated value that has a tolerance that would allow the actual value to be somewhat different.
nomograph-viscosity index An ASTM-produced chart used to plot the viscosity change of turbine oils with temperature change.
nonabrasive Material that will not scratch or scar when rubbed on another surface.
nonabrasive scraper A scraper that has no abrasive materials attached to it.
NONRADAR
d. Nonradar Route A flight path or route over which the pilot is performing his own navigation. The pilot can be receiving radar separation, radar monitoring, or other ATC services while on a nonradar route.
e. Nonradar Separation The spacing of aircraft in accordance with established minima without the use of radar; e.g., vertical, lateral, or longitudinal separation.
nonradar separation [ICAO] The separation used when aircraft position information is derived from sources other than radar.
nonrepairable Something that cannot be repaired and which, therefore, renders the part nonserviceable.
nonrepairable damage Damage that requires the aircraft or aircraft component to be replaced.
nonrigid airship An engine-driven, lighter-than-air aircraft such as a blimp that uses gas pressure to maintain the shape of the craft.
nonscheduled airline An airline that does not operate according to a regularly published schedule.
nonservo brakes Brakes that do not use the momentum of the aircraft to assist in the application of the brakes.
nonskid brakes A feature found in high performance aircraft braking systems that provides wheel antiskid protection. A skid control generator unit measures the wheel rotational speed. As the wheel rotates, the generator develops a voltage and current signal. The signal strength indicates the wheel rotational speed. This signal is fed to the skid control box though the harness. The box interprets the signal and if the wheel is slowing too quickly, it signals a solenoid in the skid control valve to release the brake pressure until the wheel begins to speed up allowing the wheel to continue to rotate without skidding.
nonstandard fastener A fastener that differs in size, length, material, or finish from established and published standards.
nonstructural The portion of an aircraft that does not carry any aerodynamic loads.
nontautening dope A special formulation of aircraft dope used on heat-shrunk polyester fabric. It provides the necessary fill for the fabric, but produces a minimum of shrinkage.
NOR
NOR gate A not or logic device that will produce a voltage at its output only when there is no voltage on any input.
NORDO (No Radio). Loss of the ability to communicate by radio. Standard pilot procedures are specified in FAR 91. Radar controllers issue procedures for pilots to follow in the event of lost communications during a radar approach when weather reports indicate that an aircraft will likely encounter IFR weather conditions during the approach.
norm reference testing (NRT) System of testing where students are rank ordered in accomplishment of objectives.
normal category airplane An airplane certificated for nonacrobatic operation.
normal heptane A liquid hydrocarbon material (C7H17) having a low critical pressure and temperature and whose detonation characteristics are used in determining the octane rating of aviation gasoline.
normal operating speed The velocity obtained in level flight at design altitude of the airplane at no more than 70% of normal rated engine power.
normal operating zone (NOZ) The NOZ is the operating zone within which aircraft flight remains during normal independent simultaneous parallel ILS approaches.
normal rated power The highest power at which an engine can be operated continuously without damage.
normal refraction The refraction of a radar beam as it passes through the atmosphere due to changes in air density with height. Usually, because the atmosphere s density decreases rapidly with height, the radar beam will be deflected downward.
normal shock wave A shock wave formed ahead of an airfoil approaching the speed of sound. It is perpendicular to the path of the airfoil.
normalizing A heat treatment in which a metal is heated to its critical temperature and allowed to cool slowly in still air. Normalizing relieves stresses in the metal.
normally aspirated engine An engine that does not compensate for decreases in atmospheric pressure through turbocharging or other means.
normally closed relay A relay switch consisting of a coil or solenoid, an iron core, and movable contacts controlled by a spring. Normally closed relay contacts are held closed by the spring. When current flows through the solenoid, the contacts are opened by the magnetic pull of the electromagnetic coil.
normally open relay A relay switch consisting of a coil or solenoid, an iron core, and movable contacts controlled by a spring. Normally open relay contacts are held open by the spring. When current flows through the solenoid, the contacts are closed by the magnetic pull of the electromagnetic coil.
norm-referenced testing (NRT) System of testing where students are ranked against the performance of other students.
North American route A numerically coded route preplanned over existing airway and route systems to and from specific coastal fixes serving the North Atlantic. North American Routes consist of the following:
a. Common Route/Portion That segment of a North American Route between the inland navigation facility and the coastal fix.
b. Non-Common Route/Portion That segment of a North American Route between the inland navigation facility and a designated North American terminal.
c. Inland Navigation Facility A navigation aid on a North American Route at which the common route and/or the noncommon route begins or ends.
d. Coastal Fix A navigation aid or intersection where an aircraft transitions between the domestic route structure and the oceanic route structure.
north mark A beacon data block sent by the host computer to be displayed by the ARTS on a 360 degree bearing at a locally selected radar azimuth and distance. The North Mark is used to ensure correct range/azimuth orientation during periods of CENRAP.
north pacific An organized route system between the Alaskan west coast and Japan.
north pole The north-seeking pole of a magnet.
NOSE
northerly turning error
In the Northern Hemisphere, a weight is placed on the south-facing end of the compass needle to compensate for dip (See dip). When a turn is made toward the north from a westerly or easterly heading the dip weight causes the compass to overshoot the actual heading. When turning toward the south, the heading is undershot. The effects are reversed in the Southern Hemisphere if the compass is compensated with a weight on the north-facing end of the compass needle.nose cone A conical-shaped dome usually attached to the front portion of a fuselage to house the radar antenna or other electronic equipment. A nose cone can also be described as the front cover of propellers, intakes for jet engines, etc., for streamlining and directing the airflow.
nose gear The forward gear on an aircraft equipped with tricycle landing gear.
nose heavy A condition that exists on an aircraft in which the center of gravity is ahead of the forward limit.
nose rib A false, or partial, wing rib extending back from the leading edge only to the main spar. Its purpose is to add smoothness to the leading edge of a wing.
nose section The forward section of an aircraft.
NOT gate A logic device having one input and one output. There will be no voltage on the output when a voltage appears at the input.
NOTAM [ICAO] A notice, containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations.
I Distribution. Distribution by means of telecommunication.
II Distribution. Distribution by mean other than telecommunications.
NOTAM(D) A (distant) NOTAM that is disseminated for all navigational facilities which are part of the U.S. airspace system, all public use airports, seaplane bases, and heliports listed in the A/FD.
NOTAM(L) A (local) NOTAM that is distributed locally only and is not attached to an hourly weather report.
notes Specific instructions on an aircraft drawing.
notice to airmen (NOTAM) A notice containing information (not known sufficiently in advance to publicize by other means) concerning the establishment, condition, or change in any component (facility, service, or procedure of, or hazard in the National Airspace System) the timely knowledge of which is essential to personnel concerned with flight operations.
a. NOTAM(D) A NOTAM given (in addition to local dissemination) distant dissemination beyond the area of responsibility of the Flight Service Station. These NOTAMs will be stored and available until cancelled.
b. NOTAM(L) A NOTAM given local dissemination by voice and other means, such as telautograph and telephone, to satisfy local user requirements.
c. FDC NOTAM A NOTAM regulatory in nature, transmitted by USNOF and given system wide dissemination.
Notices To Airmen Publication (NOTAM) A publication issued every 28 days, designed primarily for the pilot, which contains current NOTAM information considered essential to the safety of flight as well as supplemental data to other aeronautical publications. The contraction NTAP is used in NOTAM text.
nozzle The tapered end of a duct.
nozzle blades Any of the blades of a nozzle diaphragm.
nozzle diaphragm A ring of stationary blades in a turbine engine ahead of the turbine wheel. Used to direct the flow of hot gases into the turbine for maximum efficiency.
nozzle, fuel The pressure-atomizing unit that receives fuel under high pressure from the fuel manifold and
delivers it to the combustor in a highly atomized, precisely patterned spray.
NPN transistor A three-element semiconductor made up of a sandwich of P-type silicon or germanium between two pieces of N-type material.
N-strut Struts of a biplane near the wing tips shaped in the form of the letter N.
N-type semiconductor material A semiconductor material that has been doped (an impurity added) that leaves the outer ring of the valence shells with electrons that are readily given up.
N-type silicon Silicon that has been doped with an impurity having five valence electrons.
nuclear energy Energy released as a result of either nuclear fission, nuclear fusion, or radioactive decay. Nuclear fusion is not yet commercially feasible.
nuclear fission The splitting of an atomic nucleus resulting in the release of energy.
nuclear fusion The union of atomic nuclei of certain light elements to form heavier nuclei resulting in the release of energy.
nuclei Plural of nucleus.
nucleonics The branch of science that deals with atomic nuclei and nuclear energy.
nucleus 1. The center or core around which other parts are grouped. 2. The center or core of an atom consisting of positively charged protons and uncharged neutrons.
nucleus of an atom In chemistry, the central portion of an atom.
null An indicated low or zero point in a radio signal.
null balance An electrical circuit in which two voltages have cancelled each other out.
null detector An electrical instrument that determines values by adjusting a known quantity until it is identical with the quantity to be measured. Often utilizes a Wheatstone bridge.
numbers A symbol used to assign a value of quantity or placement in a sequence.
numerator The part of a fraction that illustrates a portion of something that makes up a whole. In decimals, the numerator is the number to the right of the decimal point. In a fraction, it is the number above the line and signifies the number of parts of the denominator used.
numerical control Allows more precise control of operations than analog control. Also referred to as digital control.
numerical weather prediction Meteorological forecasting using digital computers to solve mathematical equations that describe the physics of the atmosphere; used extensively in weather services throughout the world.
NUT
numerous targets vicinity (location) A traffic advisory issued by ATC to advise pilots that targets on the radar scope are too numerous to issue individually.
nut An internally threaded collar used to screw onto bolts or screws to form a complete fastening device.
nutation The wobbling of the axis of a spinning body such as the Earth, or a gyroscope.
nutplate A nut that can be riveted to the inside of a structure. Bolts and screws can be screwed into the nutplate without a wrench to hold the nut in place.
nylon A tough, lightweight, elastic polyamide material used especially in fabrics and plastics.