Definition
The vertical speed at which an aircraft is losing altitude, expressed in feet per minute (fpm) and indicated by the vertical speed indicator (VSI).
Plain English
How fast the airplane is going down, measured in how many feet of altitude it loses each minute.
Context Anchor
Seen when discussing glides, gliding turns, landing approaches, and any situation where the pilot must judge how quickly the airplane is losing height.
Derivation
Rate comes from an older meaning of a measured amount, and descent comes from Latin words meaning “to climb down.” Together, the phrase points to a measured amount of downward movement over time.
Why Pilots Care
Controlling rate of descent in glides determines whether the aircraft can reach the intended landing spot without running out of altitude or airspeed.
Intuition Check
Do not confuse rate of descent with how steep the airplane’s path looks. Rate of descent is about altitude lost per unit of time, not just the visual angle of the glide.
Example Sentence 1
The instructor noted that banking steeply in the gliding turn increased the rate of descent.
Example Sentence 2
Extending flaps increased the rate of descent and required a slight nose-up adjustment to maintain the target airspeed.