Definition
A pilot action of retarding the throttle to its lowest normal operating position, reducing engine power output to the minimum setting that still keeps the engine running smoothly. In a descent, this configuration lets the airplane lose altitude while the engine continues to operate at its lowest steady power output.
Plain English
Pulling the throttle all the way back so the engine is producing as little power as it can while still running normally.
Context Anchor
Used during descents, glide practice, landing practice, and other maneuvers where the pilot needs the airplane to descend with little or no engine help.
Derivation
‘Idle’ comes from the Old English ‘idel’, meaning ‘empty’ or ‘doing nothing useful’. An idling engine is running but not doing useful work — it is producing only enough power to keep itself turning.
Why Pilots Care
Establishes the correct descent rate and airspeed while avoiding sudden engine temperature changes.
Analogy
Like taking your foot completely off the gas pedal so a car coasts downhill.
Intuition Check
Do not read idle as engine off. In this context, idle means the engine is still running, but at its lowest normal power setting.
Example Sentence 1
Approaching the descent point, the pilot reduced power to idle and lowered the nose to begin a steady descent.
Example Sentence 2
After setting power to idle, the student maintained the recommended pitch attitude to control descent rate.