Glossary of Terms
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Near-parallel runwaysNear-parallel runways. Non-intersecting runways whose extended centre lines have an angle of convergence/divergence of 15 | |
NewtonNewton (N). The force which when applied to a body having a mass of 1 kilogram gives it an acceleration of 1 metre per | |
NEXRADNEXRAD or Nexrad (Next-Generation Radar) is a network of 159 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United States Department of Commerce, the Federal Aviation Administration(FAA) within the Department of Transportation, and the U.S. Air Force within the Department of Defense. It's technical name is WSR-88D, which stands for Weather Surveillance Radar, 1988, Doppler. NEXRAD detects precipitation and atmospheric movement or wind. It returns data which when processed can be displayed in a mosaic map which shows patterns of precipitation and its movement. The radar system operates in two basic modes, selectable by the operator – a slow-scanning clear-air mode for analyzing air movements when there is little or no activity in the area, and a precipitation mode, with a faster scan for tracking active weather. NEXRAD has an increased emphasis on automation, including the use of algorithms and automated volume scans. | |
NightThe hours between the end of evening civil twilight and the beginning of morning civil twilight or such other period.
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Night-Ireland“night” means the hours between the end of evening civil twilight and the beginning of | |
NMNautical mile (NM). The length equal to 1 852 metres exactly. | |
Non-instrument runwayNon-instrument runway. A runway intended for the operation of aircraft using visual approach procedures. | |
Normal operating differential pressure‘Normal operating differential pressure’ means the pressure differential between the cabin | |
NOSIGThe trend forecast shall indicate significant changes in respect of one or more of the elements: surface wind, visibility, NOTE : Refer to ICAO Annex 3, 2.2 - 2.2.7 | |