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Reduced vertical separation minima or minimum (RVSM) is the reduction of the standard vertical separation required between aircraft flying between FL290 (29,000 ft) and FL410 (41,000 ft) inclusive, from 2,000 feet to 1,000 feet (or between 8,850 and 12,500 m from 600 m to 300 m). This therefore increases the number of aircrafts that can safely fly in a particular volume of airspace. Historically, standard vertical separation was 1,000 feet from the surface to FL290, and 2,000 feet above FL290. This was because the accuracy of the pressure altimeter (used to determine altitude) decreases with height. Over time, air data computers (ADCs) combined with altimeters have become more accurate and autopilots more adept at maintaining a set level, therefore it became apparent that for many modern aircraft, the 2,000 feet separation was too cautious. It was therefore proposed by ICAO that this be reduced to 1,000 feet. In the US this program was known as the ''Domestic Reduced Vertical Separation Minimum'' (DRVSM). ==Implementation== Between 1997 and 2005 RVSM was implemented in all of Europe, North Africa, Southeast Asia and North America, South America, and over the North Atlantic, South Atlantic, and Pacific Oceans. The North Atlantic implemented initially in March 1997 at flight levels 330 through 370. The entire western hemisphere implemented RVSM FL290–FL410 on January 20, 2005. Africa implemented it on September 25, 2008. The People's Republic of China implemented metric RVSM on 21 November 2007.〔(CAAC RVSM FLIGHT LEVEL ALLOCATION SCHEME on China RMA )〕 But Hong Kong FIR continued to use flight levels in feet.〔(Hong Kong AIP )〕 The Russian Federation implemented RVSM and flight levels in feet on November 17, 2011. Below transition level, however, meters are still in use. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Reduced vertical separation minima」の詳細全文を読む スポンサード リンク
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