Definition
The angle between the airplane's descent path and the horizon when the engine is producing no thrust and the airplane is descending under the combined effects of gravity and aerodynamic forces. For any given airplane configuration, this angle is determined primarily by airspeed and configuration (flaps, gear, windmilling propeller), and reaches its shallowest value at the airplane's best glide speed.
Plain English
How steeply the airplane comes down when the engine isn't pulling. Fly at the right speed and the descent is as shallow as that airplane can manage; fly faster or slower than that and the airplane comes down more steeply.
Context Anchor
Encountered during engine-failure practice, emergency approach planning, and judging whether a selected landing area is within gliding distance.
Derivation
Glide comes from an old word meaning to move smoothly. Angle means the amount of slope between two lines. Together, the phrase points to the slope of the airplane’s smooth, unpowered path through the air.
Why Pilots Care
It determines how far the airplane can travel forward for each foot of altitude lost, directly affecting the pilot's ability to reach a suitable landing spot after engine failure.
Grounding Statement
In a power-off glide, the airplane is trading altitude for forward distance.
Intuition Check
Power-off glide angle is not the same as the airplane’s nose position. It is the actual downward path the airplane follows while gliding without useful engine power.
Example Sentence 1
After the engine quit, the pilot pitched for best glide speed to achieve the shallowest power-off glide angle and stretch the distance toward the nearest field.
Example Sentence 2
Knowing the airplane's power-off glide angle allowed the pilot to judge whether the field ahead was reachable without power.