Definition
The airspeed that produces the greatest forward distance traveled per foot of altitude lost when the airplane is gliding without engine power. It corresponds to the lift-to-drag ratio's maximum point for a given configuration and weight, and is published in the Pilot's Operating Handbook for each airplane.
Plain English
The speed that lets the airplane glide the farthest after losing engine power. Fly faster or slower than this speed and the airplane will come down sooner and reach less ground.
Context Anchor
You will use this term during glide practice and during an engine-out procedure, when you need to stretch the airplane’s glide to reach a safe landing area.
Derivation
Glide comes from an old word meaning to move smoothly. That helps here because the airplane is not being pulled along mainly by engine power; it is smoothly descending through the air while trading altitude for distance.
Why Pilots Care
It determines how far the airplane can travel to reach a suitable landing site after a total power loss.
Grounding Statement
Picture the engine going quiet: best glide airspeed is the target speed that gives you the most distance from the altitude you still have.
Intuition Check
Best does not mean the slowest speed, the most comfortable speed, or the speed with the least descent. Here, best means the speed that gives the greatest glide distance for the altitude lost.
Example Sentence 1
When the engine quit, the pilot pitched for best glide airspeed and turned toward the nearest field.
Example Sentence 2
The checklist directs the pilot to maintain best glide airspeed while configuring the aircraft for a forced landing.