Definition
The airspeed at which an airplane achieves its most efficient unpowered descent, typically the speed that produces the greatest distance forward per unit of altitude lost (best glide speed) or, in some contexts, the minimum rate of descent. Best glide speed is published in the Pilot's Operating Handbook for a specific weight and configuration.
Plain English
The speed to fly when the engine has failed or is at idle, so the airplane travels the farthest before it reaches the ground.
Context Anchor
You will see this term in engine-out practice, power-off approaches, and stall discussions, especially when an airplane is slow and descending in the traffic pattern.
Derivation
Glide comes from an old word meaning to move smoothly. In aviation, it points to the airplane continuing forward through the air while descending, even when engine power is low or absent.
Why Pilots Care
Flying at glide speed after an engine failure maximizes the distance available to reach a safe landing site.
Intuition Check
Do not read glide speed as just any speed while descending. In this context, it means a target speed for a controlled glide, and that target may be different from normal approach speed.
Example Sentence 1
After the engine lost power, the pilot pitched for glide speed and turned toward the nearest field.
Example Sentence 2
During cross-control stall practice, the instructor reminded the student to maintain glide speed on the approach.