Definition
A display showing how fast a value is changing over time, rather than the value itself. On a vertical speed indicator (VSI) tape, the rate indication shows the aircraft's rate of climb or descent in feet per minute, not the current altitude.
Plain English
A reading that tells you how quickly something is changing, not what it currently is. The VSI's rate indication tells you how fast you're going up or down, not how high you are.
Context Anchor
Seen on glass-panel flight displays, especially on the vertical speed tape beside the altitude display.
Derivation
Rate' comes from Latin rata, meaning a measured or reckoned amount, and in modern use means a quantity measured per unit of time (miles per hour, feet per minute). 'Indication' comes from Latin indicare, to point out. Together: a display that points out how fast something is changing.
Why Pilots Care
It lets the pilot hold a steady climb or descent rate to meet altitude restrictions and avoid unsafe vertical speeds.
Intuition Check
Do not read “rate indication” as just any number on the screen. Here, “rate” means change over time, and “indication” means what the instrument is showing, not a guarantee that the value is perfectly exact.
Example Sentence 1
The VSI tape gave a clear rate indication of 700 feet per minute descent during the approach.
Example Sentence 2
The pilot reduced power to bring the rate indication down to 500 feet per minute on final approach.