Definition
The readings shown on the vertical speed indicator (VSI), which display the rate at which the aircraft is climbing or descending, expressed in feet per minute. In straight-and-level flight, these indications should remain at zero; any deflection up or down signals a pitch change away from level flight.
Plain English
What the climb/descent rate gauge is showing you. In level flight it should sit on zero. If the needle moves up, you're climbing; if it moves down, you're descending.
Context Anchor
Seen during the instrument scan, especially when checking pitch control in straight-and-level flight.
Derivation
“Vertical” means up and down. “Speed” means rate of movement. “Indication” means a displayed sign or reading. Together, the phrase means displayed readings of how fast the aircraft is moving up or down.
Why Pilots Care
Misreading these indications leads to unintended altitude changes and loss of precise altitude control.
Grounding Statement
In level flight, a steady vertical speed indication near zero means the aircraft is not climbing or descending.
Intuition Check
Do not read “speed” here as forward speed through the air. Vertical speed indications are about upward or downward movement, not how fast the aircraft is moving forward.
Example Sentence 1
During level cruise, the pilot noticed small vertical speed indications of 100 feet per minute up and applied slight forward pressure to return to level flight.
Example Sentence 2
Steady vertical speed indications near zero confirmed proper pitch for straight-and-level cruise.