Definition
Application of the rudder pedal to its full mechanical travel in the desired direction, producing the maximum rudder deflection the airplane is designed to allow.
Plain English
Pushing one rudder pedal all the way to the floor so the rudder swings as far as it will go.
Context Anchor
Used in spin entry descriptions, where the pilot may be told to apply full rudder in the direction of the intended spin.
Derivation
Rudder comes from an old word for a steering oar used on boats. That helps because an airplane rudder also steers direction, but it does it in the air by moving the nose left or right around the vertical axis.
Why Pilots Care
Full rudder creates the strong yaw needed to enter a spin or to stop rotation during recovery; insufficient deflection often prevents a clean spin or delays recovery.
Intuition Check
Full does not mean “press hard” or “use a lot.” Here it means the pedal is moved all the way to its physical limit in the chosen direction.
Example Sentence 1
As the airplane reached the stall, the pilot applied full rudder to enter the spin.
Example Sentence 2
During recovery, apply full opposite rudder to stop the spin rotation, then neutralize the controls.