the Aviation Dictionary

epicyclic gear train - etching
epicyclic gear train -An arrangement of gears in which equivalent circuit - A circuit containing only one or
one or more gears travel around the circumference of two components that has the same properties as a more
another gear.
complex circuit. Used to more easily analyze the
epoxy - A flexible, thermosetting resin made by the
characteristics of the circuit.
polymerization -
of an epoxide. It is noted for its equivalent flat plate area - The area of a square flat
durability and chemical resistance.
-plate, normal io the direction of motion, which offers
the same amount of resistance to motion as the body or
combination of bodies under consideration.
epoxy primer - A two-part catalyzed paint material
used to provide a good bond between a surface and the
topcoat.
epoxy resin - A common thermoset material used in
aircraft construction. Used as the bonding matrix to
distribute the stresses to the fibers, and hold the fibers
together. When mixed with a catalyst, they are
adhesive, resistant to chemicals, are water resistant,
and are unaffected by heat or cold. One part of a twopart
system which combines the resin and the catalyst
to form the bonding matrix. In composites, the term
"resin" is often used to describe the two parts mixed
together.
EPR-rated gas turbine - A method of expressing the
thrust of a gas turbine engine in terms of engine
pressure ratio (EPR).
equalization -The process of restoring all of the cells of
a nickel-cadmium battery to a condition of equal
capacity. All of the cells are discharged, shorted out,
and allowed to "rest." The battery is then said to be
equalized and ready to receive a fiesh charge.
equalizer circuit - A circuit in a multiple-generator
voltage-regulator system that tends to equalize the
current output of the generators by controlling the field
currents of all the generators in the system.
equilibrium - A condition that exists within a body
when the sum of the moments of all of the forces acting
on the body is equal to zero.
equilibrium level - The altitude where the updraft
temperature is equal to its surroundings.
equinox - Noon on the day when the sun's rays are
perpendicular to the earth's surface at the equator.
equipment -Any item that is secured in a fixed location
to the aircraft and is to be utilized in the aircraft.
equipment ground - In electricity, a ground connected
to the case or chassis of electronic equipment. The
chassis is in turn, connected to an earth ground. See
also earth ground.
equipment list - A comprehensive list of equipment
installed on a particular aircraft. This includes the
required and optional equipment.
equivalent airspeed (EAS)- The calibrated airspeed,
shown on the airspeed indicator, corrected for errors
that are caused by the compressibility of the air inside,
the pitot tube, or by the installation of the instrument.
Aircraft Technical Book Company
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equivalent monoplane - A monoplane wing with equal
lift and drag properties as a combination of two or
more wings.
equivalent shaft horsepower (ESHP) - A unit of
measured power output of turboprops and some
turboshaft engines. Where ESHP equals SHP plus HP
fiom jet thrust (HP from jet thrust equals static thrust
divided by 2.6).
erosion - The removal of material by abrasion,
dissolution, andor corrosion.
escape velocity - The speed an aircraft or missile must
reach in order for it to escape from the gravitational
field of the Earth.
escutcheon - A reinforcement around a hole or opening
in a material that helps prevent tearing out of the base
material.
established - To be stable or fixed on a route, route
segment, altitude, heading, etc.
estimated ceiling - A ceiling value that derives from an
estimate made by an observer or when the method of
determining ceiling does not fall definitively in any
other category.
estimated elapsed time IICAO] - The estimated time
required to proceed from one significant point to
another.
estimated off-block time [ICAO]- The estimated time
at which the aircraft will commence movement
associated with departure.
estimated position error (EPE)- A measure of the
current estimated navigational performance. Also
referred to as Actual Navigation Performance (ANP).
estimated time enroute - The estimated flying time
from departure point to destination (lift-off to
touchdown).
estimated time of arrival - The time the flight is
estimated to arrive at the gate (scheduled operators) or
the actual runway on times for nonscheduled operators.
etch - To chemically remove a part of a material. Clad
aluminum alloy sheets are etched before painting to
microscopically roughen them so that the primer can
bond tightly to their surface.
etching - A process of detecting defects in aluminum
alloy by use of a caustic soda and nitric acid solution.