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Authorization. A list of the items that must be included in an annual or 100-hour inspection is included in
14 CFR 43, Appendix D.
one-shot rivet gun (sheet-metal working tool). A hard-hitting air hammer, used to drive large, solid
aluminum alloy rivets. A one-shot rivet gun hits the rivet with a single hard blow each time the trigger is
pulled. This is different from the action of an ordinary rivet gun, which delivers a continuous series of
blows as long as the trigger is held down.
Aluminum alloy rivets are strain hardened by repeated hammering, and they can become so brittle
they crack. To prevent this, they can be driven with a single hard blow from a one-shot rivet gun.
on-speed condition (propeller governor condition). The condition of a propeller governor when the
engine is turning at the speed selected by the governor. The centrifugal force acting on the flyweights in the
governor is exactly balanced by the compression of the speeder spring.
open angle (sheet metal forming). An angle in which sheet metal is bent less than 90°.
open-assembly time (adhesive consideration). The amount of time allowed to elapse between the
spreading of an adhesive on the surfaces to be joined and the time the surfaces are clamped together.
open-center hydraulic system. A fluid power system in which the selector valves are arranged in series
with each other. Fluid flows from the pump through the center of all of the selector valves, back into the
reservoir when no unit is being actuated.
open-center selector valve (hydraulic system component). A type of selector valve that functions as an
unloading valve as well as a selector valve. All open-center selector valves are installed in series, and when
no unit is being actuated, fluid from the pump flows through the centers of all of the valves and returns to
the reservoir.
When a unit is selected for actuation, the center of the selector valve is shut off and the fluid from
the pump goes through the selector valve into one side of the actuator. Fluid from the other side of the
actuator returns to the valve and goes back to the reservoir through the other selector valves. When the
actuation is completed, the selector valve is placed in its neutral position. Its center opens, and fluid from
the pump flows straight through the valve, unloading the pump.
open circuit (electrical circuit condition). A condition in which there is no complete path for electrons to
flow from one terminal of the source of electrical energy to the other terminal.
open-circuit voltage. The voltage of a battery measured when it is supplying no current to the circuit.
Open-circuit voltage is higher than closed-circuit voltage because there is no voltage drop across internal
resistance of the battery.
open-end wrench (mechanic’s hand tool). A hand tool used by mechanics to turn nuts and bolts. The jaws
of the wrench are in the form of a slot with parallel sides that fit the nut or the bolt head. These jaws are
usually offset from the axis of the handle by about 15°.
open-hearth furnace. A furnace used for melting metals. Pig iron and scrap metal are placed in a shallow
hearth within the furnace and are melted by heat supplied by a direct flame and from radiation from the
walls and ceiling of the furnace.
open wiring (aircraft electrical system installation). Electrical wiring installation in which the wires are
tied together in bundles and clamped to the aircraft structure rather than being enclosed in conduit.
operate. 14 CFR Part 1: “Use, cause to use or authorize to use aircraft, for the purpose (except as provided
Printed from Summit Aviation's Computerized Aviation Reference Library, 2/7/2007
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in § 91.13 of this chapter) of air navigation including the piloting of aircraft, with or without the right of
legal control (as owner, lessee, or otherwise).”
operating cycle (turbine engine operation). One complete series of events in the operation of a gas
turbine engine that consists of starting the engine, taking off, landing, and shutting the engine down.
operate time (electrical relay). The time measured from the instant a relay control switch closes until the
relay contacts are fully open or fully closed.
operational amplifier (electronic circuit). A two-input linear amplifier, often built into a single integrated
circuit (IC) chip. The output is an amplification of the difference between the signals on the two inputs. An
operational amplifier is commonly called an op-amp.
operational CG (weight and balance). The center of gravity of an aircraft when it is loaded for flight.
operational control. 14 CFR Part 1: “With respect to a flight, means the exercise of authority over
initiating, conducting or terminating a flight.”
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航空术语词典Dictionary of Aeronautical Terms 中(155)
