Definition
A flight condition in which the engine is producing no thrust, with the throttle fully closed (at idle) so that the aircraft is operating purely on the energy from its airspeed and altitude. Power-off performance figures, such as power-off stall speeds, are measured under this condition.
Plain English
The engine is at idle and not producing useful thrust, so the airplane is gliding or descending on its own energy.
Context Anchor
Seen in stall speed performance charts and stall practice, where power setting changes how the airplane behaves near a stall.
Why Pilots Care
Power-off stall speeds are used to determine minimum safe speeds for landing approaches and emergency procedures.
Grounding Statement
Picture the throttle pulled back to idle: the airplane must keep flying mainly from its wing and airspeed, not from the engine helping it along.
Intuition Check
Power-off does not usually mean the engine is shut down. In this context, it means the engine is set so it is providing little or no useful help to the airplane’s flight.
Example Sentence 1
The pilot reduced the throttle to idle and held the nose up to demonstrate a power-off stall.
Example Sentence 2
During the power-off stall demonstration, the aircraft stalled at a higher speed than with power applied.