時(shí)間：2011-03-11 23:11來源：藍(lán)天飛行翻譯 作者：admin 點(diǎn)擊：次
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depth gage. An instrument used to measure the depth of a hole or groove. The measuring scale protrudes from the center of a flat blade. The blade is laid across the top of the hole or groove, and the measuring scale is pushed to the bottom. The amount the scale sticks out of the blade is the depth of the hole or groove. Depth gages are used to measure the depth of the tread on aircraft tires. depth micrometer. A precision measuring instrument which uses a standard micrometer caliper head mounted in a flat-ground bar. The distance the spindle sticks out of the bar is read in thousandths of an inch. Depth micrometers are used to measure the depth of machined grooves. derate. To reduce the power output allowed for an engine or the voltage or current allowed for an electrical component. Derating is done to extend the life or reliability of a device. Newly designed aircraft engines are quite often placed in service with a lower power rating than they are designed to produce — they are derated. As operational experience is gained, the rated power is increased. derichment (fuel metering system operation). A condition in the fuel metering system of a large reciprocating engine in which the fuel-air mixture is leaned out, or deriched, when antidetonation injection (ADI) fluid is injected into the engine. If the mixture were not leaned, the addition of the ADI fluid would enrich the mixture so much the engine could not produce its maximum power. descent (aircraft flight condition). A decrease in altitude. descent speed adjustments (air traffic control). Speed decrease calculations made to determine an accurate vertex time of arrival (VTA). These calculations start at the transition point and use arrival speed segments to the vertex. desiccant. A material, such as silica gel, that is able to absorb moisture from the air. When precision equipment is stored, bags of silica gel are packed with it. The silica gel absorbs moisture from the air and prevents the moisture damaging the equipment. In pneumatic power systems, the high-pressure compressed air passes through a desiccant which absorbs all the moisture in the air. If moisture were left in the air, it would freeze when the air expands and its temperature drops. design load. The maximum load a component is designed to carry. The design load is made up of the actual load the component is expected to encounter, plus a factor of safety. destructive testing. A method of testing that results in the destruction of the part being tested. Destructive testing is normally an engineering procedure, used to determine the ultimate strength of a device or part, and to identify its weakest point. detachable part. A part of a component which can be removed without damaging the component. detail drawing (aircraft mechanical drawing). A drawing that contains enough information to allow a component to be fabricated. detector (electronic component). A rectifier in an electronic circuit. The term detector is normally used for a rectifier that changes modulated radio-frequency alternating current into pulsating direct current whose amplitude varies in the same way as the modulation on the original AC. |
