时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
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ground speed (aircraft navigation). The speed at which an aircraft is moving over the ground. When an aircraft is flying, its speed through the air is its airspeed. The air moves over the ground and carries the aircraft with it, so the ground speed is the vector sum of the airspeed and the direction of flight of the aircraft, combined with the speed and direction of the air movement over the ground (the wind speed and direction). If the air is moving in the same direction the aircraft is flying, the ground speed is equal to the airspeed plus the speed of the air movement. If the wind is blowing in the direction opposite that which the aircraft is flying, the ground speed is equal to the airspeed minus the speed of the wind. When the wind is blowing at an angle to the flight path, the ground speed is found by adding the airspeed and the wind speed as vectors. ground support equipment (aircraft operations). All the equipment needed to service and maintain aircraft on the ground. Ground support equipment includes such equipment as tugs to move the aircraft and auxiliary power units to provide electrical power and compressed air when the engines are not running. ground visibility. 14 CFR Part 1: “Prevailing horizontal visibility near the earth’s surface as reported by the United States National Weather Surface or an accredited observer.” ground wave (radio transmission). The component of a transmitted electromagnetic wave that travels from the transmitting antenna along the surface of the earth. growler. A piece of electrical test equipment used to check armatures in DC motors and generators for open or shorted turns in the windings. The armature to be tested is placed on the growler, and the AC power is turned on. The growler acts as the primary of a transformer and the armature as the secondary. A voltmeter is used to measure the voltage induced into the armature windings. A growler gets its name from the growling noise made when an armature is being tested. GTAW (gas tungsten arc welding). A method of electric arc welding in which the electrode in the torch is a fine, nonconsumable tungsten wire. The arc is enveloped in a flow of an inert gas such as argon or helium. GTAW was formerly called heli-arc welding. guarded switch (type of electrical switch). A special switch whose operating control is inside a guard that must be raised before the switch can be actuated. Guarded switches are used for circuits that must not be accidentally operated. gudgeon pin (reciprocating engine component). The British name for the wrist pin in a reciprocating engine. See wrist pin. GUMP. An acronym used by a pilot for a pretakeoff check to be sure that none of the most important items are missed: G — Gasoline (The correct fuel tank should be selected for takeoff.) U — Undercarriage (The landing gear selector should be in the down position and the indicator lights show that the gear is locked down.) |
