the Aviation Dictionary

of time, in hours, that the battery can supply this
current.
ampere-hour meter - An electrical measurement
instrument that measures the rate of current flow per
unit of time.
amphibian - An aircraft designed to land on and take
off from either land or water.
amphibious floats - Floats that can be attached to an
aircraft to allow it to operate from either land or water.
Retractable wheels are mounted in the floats and can be
extended for o~eration on the land.
amplification - The increase in either voltage or current
that takes place in a device or in an electrical circuit.
amplification factor - The ratio of the output amplitude
of an electrical or electronic circuit to its the input
amplitude.
amplifier - An electronic device that increases the
amplitude of a signal relative to the amplitude of its
input.
amplitude - The magnitude or amount a value changes
from its at-rest condition, or its normal condition, to its
maximum condition. In wave motion, one half the
distance between the wave crest and the wave trough. -
amplitude modulation - A system of varying the
amplitude in a radio-frequency carrier wave so that it
can carry information.
AMS specifications - Specifications for aircraft
components that conform to established engineering
and metallurgical practices in the aircraft industries.
AMS specifications are developed by the SAE
Aeronautics Committee.
AN aeronautical standard drawings - Dimensional
standards for aircraft fasteners developed by the
Aeronautical Standards Group. AN is the part number
orefix for all fasteners that are described in these
drawings. -
AN fittings - A series of fittings for flared tubing, using
a 37" flare angle and having a small shoulder between
the ends of the threads and the beginning of the flare
cone. Included in the listing of parts whose design and
material have been amroved bv both the United States
A -
Air Force and Navy and are acceptable for use in
civilian and military airplanes.
AN hardware - Standard hardware items such as bolts,
nuts, washers, etc., whose design and material has been
approved by both the United States Air Force and Navy
and are acceptable for use in civilian and military
airplanes.
A-N radio range - An early, obsolete navigational aid.
Two antennas radiate signals that are heard on a lowfrequency
receiver as an "N" (dah-dit) on one side of
the desired track and an "A" (dit-dah) on the other.
ampere-hour meter . aneroid barometer
When on track, the signal received sounds as a steady
tone.
anaerobic resin - A single-component polyester resin
that hardens when all air is restricted from it.
analog - A physical variable that keeps a fixed
relationship with another variable as it changes. For
exam~le. the ~osition of the hands of a clock keep a
fixed relationship with time. It is because of this
relationship that we can tell the time of day by
knowing the positions of the hands of the clock. The
position of the clock hands is an analog of time.
analog computer - An electronic computer that
operates by converting different levels of voltage or
current into numerical values.
analog data - Data represented by a continuously
varying voltage or current.
analog-to-digital conversion - An alteration that
changes analog information into a digital form.
analyzer, engine - A portable or permanently installed
instrument, whose function is to detect, locate, and
identify engine operating abnormalities such as those
caused by a faulty ignition system, detonation, sticking
valves, poor fuel injection, etc.
anchor light - A white light displayed on boats or
seaplanes indicating that they are anchored.
anchor nut - A nut riveted or welded to a structure in
such away that a screw or bolt can be screwed into it.
An anchor nut does not have to be held with a wrench
to keep it from turning.
AND gate - A logic device whose output is high only if
all inputs are high..
anemometer - An instrument that measures the velocity
of moving air. One type of anemometer uses a series of
hemispherical metal cups mounted on arms on a shaft.
The air blows the cups and rotates the shaft. A counter
measures and converts this into wind speed that may be
displayed in feet per second, meters per second,
kilometers per hour, miles per hour, or knots. Other
anemometers convert wind speed to a reading by use of
impellers or by measuring the effect of moving air on a
hot wire.
anemometer - An instrument for measuring wind
speed.
aneroid - 1. A sealed flexible container that expands or
contracts in relation to the surrounding air pressure. It
is used in an altimeter or a barometer to measure the
pressure of the air. 2. A thin disc-shaped box or
capsule, usually metallic, which is partially evacuated
of air and sealed. It expands or contracts kith changes
of the surrounding air or gas.
aneroid barometer - An instrument for measuring
atmospheric pressure, its key component is a partially
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