RVSM stands for Reduced Vertical Separation Minimum. What does this exactly mean? In more detail, RVSM is used to reduce the vertical separation of an aircraft from 2,000 feet to 1,000 feet when flying at altitudes between 29,000 feet (FL240) and 41,000 feet (FL410).
RVSM is use today because it significantly increases the number of airplanes that can fly in a defined airspace area. In theory, RVSM nearly doubles the number of airplanes per area. It also allows pilots to choose more efficient altitudes and avoid unwanted turbulence.
THE HISTORY OF RVSM
Before the development of RVSM, aircrafts flying between the surface and FL290 required 1,000 feet of vertical separation, while aircrafts flying above FL290 were required 2,000 feet of separation. This was because the accuracy of pressure altimeters decreases with higher altitude, and at the time, pressure altimeters were not reliable enough to guarantee a sufficient separation between converging aircrafts.
SEPARATION REQUIREMENTS TODAY
Today, aircrafts are more reliable when it comes to accurately determining altitudes and staying within their assigned altitudes. This is mainly due to the invention of Air Data Computers (ADCs). ADCs have advanced autopilots and increased the accuracy of aircraft altimeters; therefore, the 2,000 foot separation requirement is no longer a concern. Because the separation requirement was no longer stressed, the idea for RVSM was sparked.
RVSM was first implemented in 2005 in 48 southern states, Alaska, the Gulf of Mexico, the Atlantic High Offshore Airspace and San Juan FIR. Since RVSM’s kick off, many benefits have been reaped, including:
- Pilots can fly at more efficient altitudes with 1,000 feet of separation.
- Air Traffic Controllers can fit more jets into the sky at one time.
- Jets are saving in fuel due to more efficient altitudes – stats show that airline flights burned 2.5% less fuel per trip after RVSM was rolled out.
RVSM EQUIPMENT AND TRAINING REQUIREMENTS
Like many other requirements in the aviation industry, there are strict rules and guidelines that need to be followed in order to fly RVSM. Certified autopilots and altimeters are required and specialized pilot training needs to be completed before an aircraft can fly RVSM. If a pilot is not authorized to fly RVSM, ATC requires the pilot to fly below FL290 or above FL410 with 2,000 feet of vertical separation.