Reduced Vertical Separation Minimum (RVSM) is defined as the reduction of vertical space between aircraft from 2,000 to 1,000 feet at flight levels from 29,000 feet up to 41,000 feet. RVSM was implemented as a means to increase airspace capacity and access to more fuel-efficient flight levels. The International Civil Aviation Organization (ICAO) and its member states first mandated the implementation of RVSM in the North Atlantic in March 1997; with other regions around the world to follow.
RSVM has now been implemented globally and requires that aircraft operating between flight levels 290 and 410 (inclusive) be RVSM approved. Monitoring an aircraft’s height-keeping performance is an important part of the RVSM approval process. Monitoring supports the safety assessment and safety oversight function that is required with RVSM implementation. An operator must meet the minimum monitoring requirements for their aircraft as established by their respective State authority to maintain their RVSM approval status.
In May 2011, ICAO member states implemented a long-term RVSM monitoring policy requiring that aircraft operating within RVSM airspace complete a re-occurring monitoring flight in order to maintain their RVSM approval status. Operators must complete a RVSM monitoring flight every two years (or 1,000 hours of flight whichever is greater).