Definition
A mechanical stop or notch in the thrust lever quadrant that marks the boundary between the forward thrust range and the reverse thrust range. The thrust levers must be lifted or moved past this stop before reverse thrust can be selected, preventing accidental selection of reverse thrust in flight or at high forward power.
Plain English
A built-in catch in the throttle quadrant at the idle position. The pilot has to deliberately lift or move the levers past this catch before they can pull them back into reverse. It stops the levers being yanked into reverse by mistake.
Context Anchor
Encountered when moving the thrust or power levers to idle during landing rollout or ground operation on an airplane equipped with thrust reversers.
Derivation
Detent comes from the French détente, meaning a catch or trigger release in a mechanism. In aviation hardware, a detent is any small mechanical stop that holds a control in a defined position until deliberately moved past it. Combined with idle, it names the catch located at the idle thrust position.
Why Pilots Care
Prevents inadvertent selection of reverse thrust, which could damage engines or cause loss of directional control if deployed at the wrong time.
Intuition Check
Idle does not mean the engine is off; it means the engine is running at minimum power. Detent does not mean a label or setting only; it is a physical stop or notch the lever reaches.
Example Sentence 1
After touchdown, the pilot brought the thrust levers to idle, then lifted them over the idle detent to deploy the reversers.
Example Sentence 2
During the preflight check the pilot confirmed that both thrust levers stopped firmly at the idle detent before any further aft movement was possible.