Definition
An air traffic control standard that reduces the required vertical spacing between aircraft from 2,000 feet to 1,000 feet in the airspace between FL290 (29,000 feet) and FL410 (41,000 feet) inclusive. To operate in this airspace, aircraft must meet specific altitude-keeping equipment requirements, the operator must hold an RVSM authorization, and pilots must be trained in RVSM procedures.
Plain English
A rule that lets aircraft fly closer together vertically — 1,000 feet apart instead of 2,000 feet — at high cruising altitudes. Only aircraft with the right equipment and approval can use this airspace.
Context Anchor
Seen in instrument flight planning, high-altitude enroute operations, and discussions of aircraft approval for flight above about 29,000 feet.
Derivation
The phrase is descriptive: 'reduced' (less than before), 'vertical separation' (the up-and-down spacing between aircraft), and 'minimums' (the smallest allowable amount). It signals a tightening of the older 2,000-foot rule into a 1,000-foot rule.
Why Pilots Care
It increases the number of available flight levels, allowing more aircraft to operate efficiently without increasing collision risk.
Grounding Statement
RVSM makes more high-altitude cruising levels available by safely reducing the required vertical spacing between approved aircraft.
Intuition Check
“Reduced” does not mean air traffic control is simply accepting less safety margin. It means the spacing was reduced only for aircraft and operations that meet stricter height-keeping requirements. “Minimums” here means required aircraft spacing, not weather minimums for landing.
Example Sentence 1
Before climbing to FL350, the crew confirmed the aircraft was RVSM-authorized and that both altimeters agreed within tolerance.
Example Sentence 2
With RVSM in effect we maintained 1,000 feet vertical separation from the aircraft level at FL350.