RVSM

Reduced Vertical Separation Minima or Minimum (RVSM) is an aviation term used to describe the reduction of the standard vertical separation required between aircraft flying at levels between  FL290 (29,000 ft.) and FL410 (41,000 ft.) from 2,000 feet to 1,000 feet. This therefore increases number of aircraft that can safely fly in a particular volume of airspace.
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