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INSTRUMENT PROCEDURES HANDBOOK

REDUCED VERTICAL SEPARATION MINIMUMS

In 1960, the minimum vertical separation between airplanes above FL 290 was officially increased to 2,000 feet. This was necessary because of the relatively large errors in barometric altimeters at high altitudes. Since that time, increased air traffic worldwide has begun to approach (and sometimes exceed) the capacity of the most popular high-altitude routes. Likewise, very accurate altitude determination by satellite positioning systems makes it possible to change the minimum vertical separation for properly equipped airplanes back to the pre-1960 standard of 1,000 feet. [Figure 3-46 on page 3-41] RVSM airspace is any airspace between FL 290 and FL 410 inclusive,where airplanes are separated by 1,000 feet vertically. In the early 1980’s, programs were established to study the concept of reduced vertical separation minimums (RVSM). RVSM was found to be technically feasible without imposing unreasonable requirements on equipment. RVSM is the most effective way to increase airspace capacity to cope with traffic growth. Most of the preferred international and domestic flight routes are under both RVSM and RNP RNAV rules.

In 1997, the first RVSM 1,000-foot separation was implemented between FL 330 and FL 370 over the North Atlantic. In 1998, RVSM was expanded to include altitudes from FL 310 to FL 390. Today States (governments) around the globe are implementing RVSM from FL 290 to FL 410. There are many requirements for operator approval of RVSM. Each aircraft must be in compliance with specific RVSM criteria. A program must be in place to assure continued airworthiness of all RVSM critical systems. Flight crews, dispatchers, and flight operations must be properly trained, and operational procedures, checklists, etc. must be established and published in the Ops Manual and AFM, plus operators must participate in a height monitoring program.

Using the appropriate suffix in Block 3 on the IFR flight plan lets ATC know that your flight conforms to the necessary standards and is capable of using RNP routes or flying in RVSM airspace. The equipment codes changed significantly in 2005 and are shown in Figure 3-47.