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The switch then opens the circuit and the feathering pump stops running.
Federal Aviation Administration. See FAA.
Federal Aviation Regulations. See FAR.
Federal Communications Commission. See FCC.
feedback. A process in an electrical circuit or control system in which some energy from the output of the
system or circuit is fed back into the input. If the energy being fed back is in phase with the input signal,
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the feedback is positive and the output is increased. But if it is fed back out of phase with the input signal,
the feedback is negative and the output is decreased.
A control system using feedback is called a closed-loop system. The feedback closes the loop.
feeder fix (air traffic control). The fix depicted on instrument approach procedure charts which
establishes the starting point of a feeder route.
feeder route (air traffic control). A route depicted on instrument approach procedure charts to designate
routes for aircraft to proceed from the en route structure to the initial approach fix (IAF).
feedthrough capacitor. A capacitor used to carry a conductor through a panel or bulkhead. The outer
conductor of the capacitor is connected to the case, and the inner conductor is connected to terminals that
extend from both ends of the capacitor.
Feedthrough capacitors used in some aircraft magnetos minimize breaker point arcing and also
decrease the radio interference caused by electrical energy radiated from the ignition switch lead.
feedthrough connector. A type of electrical connector used to carry a group of conductors through a
bulkhead or panel. Feedthrough connectors do not have wires fastened to them, but rather they allow cables
on both sides of the bulkhead to be connected through them.
Sealed feedthrough connectors carry circuits through the bulkheads of pressurized aircraft.
feeler gage (precision tool). A type of measuring tool consisting of strips of precision-ground steel of
accurately measured thickness. Feeler gages are used to measure the distance between close-fitting parts,
such as the clearances in a mechanical system or the distance by which moving contacts are separated.
fence (aerodynamics). A stationary vane that extends chordwise, from the leading edge to the trailing edge,
across upper surface of the wing of a high-speed airplane. Fences prevent the air from flowing spanwise
along the wing.
Fenwal fire detection system. A patented spot-type fire detection system installed in an aircraft. This
system uses individual thermal switches connected between two insulated conductors. An open circuit in
either of the two conductors will not prevent the system from detecting a fire, but it will keep it from
indicating good when the test switch is closed.
fermium. A synthetic, metallic, radioactive chemical element. Fermium’s symbol is Fm, its atomic number
is 100, and it has mass numbers ranging between 248 and 257. Fermium was first discovered as debris from
a hydrogen bomb explosion, and it is now made in nuclear reactors.
ferrite. A material used as a core for many electromagnetic components. Ferrite is made of powdered metal
sintered and molded into the proper shape. Sintering is a process in which powdered metal is heated but not
quite melted, and then squeezed together.
Ferrite has a high permeability, it easily accepts lines of magnetic flux, but it has such a high
resistance that eddy current losses are very low.
ferrite steel. Alpha iron into which some carbon has been dissolved. It exists at temperatures below its
critical temperature.
ferromagnetic material. A material that contains iron and has a high magnetic permeability.
Ferromagnetic materials can be magnetically saturated (all the magnetic domains aligned in the same
direction). They have good retentivity; they retain a large amount of their magnetism when the magnetizing
force is removed.
ferrous metal. Any metal that contains iron and has magnetic characteristics. Magnetic characteristics
include the ability to be magnetized and to be attracted by a magnet.
ferrule resistor (electrical component). A type of resistor that has metal ferrules, or bands, around each
end so it can be mounted in a standard fuse clip.
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ferrule terminals (electrical fuse component). The terminals on each end of a tubular fuse. Ferrule
terminals are short, closed, metal caps that slip over the ends of a glass tube that contains a fuse link. The
ferrule terminals are held in fuse clips.
ferry flight. A flight for the purpose of returning an aircraft to base, delivering an aircraft from one
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航空术语词典Dictionary of Aeronautical Terms 中(32)
