the Aviation Dictionary

Nomex . nonprecision approach (NPA)
Nomexm - 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.
non-airworthiness item - An inspection item that if
broken or inoperative does not affect the airworthiness
of the aircraft.
nonapproach control tower - Authorizes aircraft to
land or takeoff at the airport controlled by the tower, or
to transit the airport Class D airspace. The primary
function of a nonapproach control tower is the
sequencing of aircraft in the traffic pattern and on the
landing area. Nonapproach control towers also separate
aircraft operating - under instrument flight - rules
clearances from approach controls and centers. They
provide ground control services to aircraft, vehicles,
personnel, and equipment on the airport movement
area.
non-aqueous developer - In dye-penetrant inspections,
a material that causes a crack to show up. Non-aqueous
developer is not water based and is less corrosive to the
part.
non-atomizing spray - The application of a material to
a surface by a spray gun in which the material is fed in
a solid stream rather than in tiny droplets.
non-atomizing spray gun - A spray gun that propels a
solid stream from the spray nozzle.
noncommon routelportion - That segment of a North
American Route between the inland navigation facility
and a designated North American terminal.
noncomposite separation - Separation in accordance
with minima other than the composite separation
minimum specified for the area concerned.
nondestructive inspection (NDI)- An inspection of
aircraft parts, units, components, etc., that doesn't alter
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or destroy the physical or material properties and/or
integrity of the part. It is used to determine the
continued serviceability. Also referred to as
nondestructive testing.
nondestructive testing (NDT) - See nondestructive
inspection (NDI).
nondimensional number - A number that does not
have a dimensional value such as a Mach speed.
nondirectional antenna - An antenna that has the
ability to receive or transmit equal signals in all
directions.
nondirectional beacon - An L/MF or UHF radio
beacon transmitting nondirectional signals whereby the
pilot of an aircraft equipped with hirection finding
equipment can determine his bearing to or from the
radio beacon and "home" on or track to or from the
station. When the radio beacon is installed in
conjunction with the Instrument Landing System
marker, it is normally called a Compass Locator.
nonferrous metal - A metal that contains no iron.
nonflexible control cable - A grouping of seven or 19
strands of solid wire preformed into a helical or spiral
shape. Can be used for straight runs where it does not
pass over any pulleys.
noninductive winding - A winding consisting of two
parts wound in such a way that the magnetic field from
one cancels the other. The result is no inductive load.
noninductlve load - An electrical load with no
inductance. The entire load is due to resistance and
capacitance.
nonlinear output - Any output not directly proportional
to the input.
nonlinear scale - The scale of an indicating instrument
in which the numbers are spread out at one end and are
bunched up at the other.
nonlinear system - Nonuniform in length, width, or
output.
nonmagnetic - Metal that does not have the properties
of a magnet and/or that cannot be magnetized or
attracted by a magnet.
nonmovement areas - Taxiways and apron (ramp)
areas not under the control of air traffic.
non-owner liability coverage - An insurance policy
against claims arising from bodily injury or damage
caused to others or their property while using an
aircraft that one does not own.
nonporous - Any material that does not allow a liquid
to pass through it.
nonprecision approach (NPA) - An instrument
approach based on a navigation system which provides