Definition
The simultaneous and proportional use of rudder and aileron inputs to produce a turn in which the airplane's longitudinal axis stays aligned with the curved flight path, with no slipping or skidding. When ailerons bank the airplane, they also create adverse yaw — a tendency for the nose to swing opposite the direction of bank — which the pilot counters with rudder pressure applied in the same direction as the aileron input.
Plain English
Whenever you roll into or out of a turn, you must press the rudder pedal on the same side as the aileron you are using. The ailerons bank the wings, but they also try to swing the nose the wrong way, and the rudder cancels that out so the airplane turns smoothly instead of sliding sideways.
Context Anchor
Seen in instrument flying when practicing turns, entering or leaving a bank, and keeping the airplane smooth while flying by reference to instruments.
Derivation
Coordination comes from the Latin co- (together) and ordinare (to arrange) — literally arranging two things to work together. Here, two separate controls are arranged to act as one combined input.
Why Pilots Care
Proper coordination keeps the airplane balanced, prevents inaccurate instrument indications, and maintains safe control especially when visibility is low.
Grounding Statement
In a smooth instrument turn, the wings bank and the nose follows the turn without sliding sideways.
Intuition Check
Coordination does not mean moving the rudder and ailerons the same amount. It means using the right amount of each so the airplane turns smoothly without the nose swinging or the airplane sliding sideways.
Example Sentence 1
Rolling into the left turn, she added a touch of left rudder to keep the controls coordinated and the ball centered.
Example Sentence 2
In the practice turn, the instructor reminded the student to coordinate rudder and aileron so the ball stayed centered.