Aviation Glossary

RVSM

RVSM airspace is where air traffic control separates aircraft by a minimum of 1,000 feet vertically between flight level (FL) 290 and FL 410 inclusive. RVSM airspace is special qualification airspace; the operator and the aircraft used by the operator must be approved by the Administrator. Air traffic control notifies operators of RVSM by providing route planing information.

source: FAA Instrument Procedures Handbook (FAA-H-8083-16)

Reduced Vertical Separation Minimums: Reduces the vertical separation between flight level (FL) 290–410 from 2,000 feet to 1,000 feet and makes six additional FLs available for operation.

source: FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25A)

REDUCED VERTICAL SEPARATION MINIMUMS (RVSM): A reduction in the vertical separation between flight levels 290 – 410 from 2000 to 1000 feet.

source: ICAO Aviation Chart Glossary

Reduced Vertical Separation Minima: the reduction of vertical separation from 2,000 to 1,000 feet with aircraft flying in opposite directions every 1,000 feet in order to accommodate more aircraft in the same airspace

source: ICAO English Pro Aviation Glossary

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 aircraft 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.

nly aircraft with specially certified altimeters and autopilots may fly in RVSM airspace, otherwise the aircraft must fly lower or higher than the airspace, or seek special exemption from the requirements. Additionally, aircraft operators (airlines or corporate operators) must receive specific approval from the aircraft's state of registry in order to conduct operations in RVSM airspace. Non RVSM approved aircraft may transit through RVSM airspace provided they are given continuous climb throughout the designated airspace, and 2,000 ft vertical separation is provided at all times between the non-RVSM flight, and all others for the duration of the climb/descent.

"State aircraft", which includes aircraft used in military, customs and police service, are exempted from the requirement to be RVSM approved. Participating states have been requested, however, to adapt their state aircraft for RVSM approval, to the extent possible, and especially those aircraft used for General Air Traffic (GAT)

source: Wikitionary / Wikipedia and Related Sources (Edited)