Reduced Vertical Separation Minima
Encyclopedia
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 above FL285 (28,500 ft.)
and up to FL410 (41,000 ft.) from 2,000 feet to 1,000 feet (or between 8,900 metres and 12,500 metres from 600 metres to 300 metres). 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, 2,000 feet from FL290 to FL410 and 4,000 feet above this. This was because the accuracy of the pressure altimeter
(used to determine altitude
) decreases with height. Over time, Air data computer
s (ADCs) combined with altimeters have become more accurate and autopilot
s more adept at maintaining a set level, therefore it became apparent that for many modern aircraft, the 2,000 foot 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).
"State aircraft", which includes military, customs and police aircraft, 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).
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
term used to describe the reduction of the standard vertical separation required between aircraft flying above FL285 (28,500 ft.)
Flight level
A Flight Level is a standard nominal altitude of an aircraft, in hundreds of feet. This altitude is calculated from the International standard pressure datum of 1013.25 hPa , the average sea-level pressure, and therefore is not necessarily the same as the aircraft's true altitude either...
and up to FL410 (41,000 ft.) from 2,000 feet to 1,000 feet (or between 8,900 metres and 12,500 metres from 600 metres to 300 metres). 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, 2,000 feet from FL290 to FL410 and 4,000 feet above this. This was because the accuracy of the pressure altimeter
Altimeter
An altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.-Pressure altimeter:...
(used to determine altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
) decreases with height. Over time, Air data computer
Air data computer
An air data computer is an essential avionics component found in modern glass cockpits. This computer, rather than individual instruments, can determine the calibrated airspeed, Mach number, altitude, and altitude trend from input data from sensors such as an aircraft's pitot-static system,...
s (ADCs) combined with altimeters have become more accurate and autopilot
Autopilot
An autopilot is a mechanical, electrical, or hydraulic system used to guide a vehicle without assistance from a human being. An autopilot can refer specifically to aircraft, self-steering gear for boats, or auto guidance of space craft and missiles...
s more adept at maintaining a set level, therefore it became apparent that for many modern aircraft, the 2,000 foot 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.Requirements
Only 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 military, customs and police aircraft, 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).
External links
- Altimetry System Error (ASE) and its effects on operations in RVSM airspace
- FAA article promoting the new rule
- Friendlier Skies - Washington Times
- RVSM on Skybrary
- Use of Trailing Cones for RVSM Certification
See also
- Acronyms and abbreviations in avionicsAcronyms and abbreviations in avionics-A:*ACARS: Aircraft Communications Addressing and Reporting System.*ACAS: Airborne Collision Avoidance System.*ACP: Audio Control Panel.*ACS: Audio Control System.*ADAHRS: Air Data and Attitude Heading Reference System.*ADC: Air Data Computer....
- Air safetyAir safetyAir safety is a term encompassing the theory, investigation and categorization of flight failures, and the prevention of such failures through regulation, education and training. It can also be applied in the context of campaigns that inform the public as to the safety of air travel.-United...
- Flight levelFlight levelA Flight Level is a standard nominal altitude of an aircraft, in hundreds of feet. This altitude is calculated from the International standard pressure datum of 1013.25 hPa , the average sea-level pressure, and therefore is not necessarily the same as the aircraft's true altitude either...
- Strategic Lateral Offset ProcedureStrategic Lateral Offset ProcedureStrategic Lateral Offset Procedure is an en route high altitude procedure used by pilots of turbojet and turboprop aircraft navigating an assigned route along an airway or between published navigational fixes by adjusting their course to parallel the assigned route either 1 NM or 2 NM to the right...
- TCAS