Definition
A turn in which the aircraft is either slipping (sliding toward the inside of the turn) or skidding (sliding toward the outside of the turn) because the bank angle and the rate of yaw are not properly matched. In an uncoordinated turn, the inclinometer ball is not centered, indicating that the lift vector and the centrifugal force on the aircraft are not aligned with the pilot's vertical axis.
Plain English
A turn that is sloppy because the aircraft is sliding sideways through the air, instead of carving cleanly around the curve. The little ball in the turn instrument is off to one side rather than sitting in the middle.
Context Anchor
Seen in instrument flying, attitude instrument training, and discussions of body-sense illusions during turns.
Derivation
From 'coordinate' (Latin co- 'together' + ordinare 'to arrange'), meaning to make things work together. An 'uncoordinated' turn is one where the controls — bank, rudder, and elevator — are not working together in the right amounts, so the airplane and the air are out of step.
Why Pilots Care
Uncoordinated turns waste energy, increase stall risk on the inside wing, and can cause spatial disorientation when flying by instruments.
Analogy
It is like a car turning on a slick road while sliding a little sideways. The car is still turning, but the sideways slide means the turn is not clean and balanced.
Grounding Statement
If the airplane is turning and you feel pushed sideways in the seat, or the ball is not centered, the turn is uncoordinated.
Intuition Check
Uncoordinated does not mean the pilot is generally disorganized or that the airplane is going the wrong direction. Here it means the turn is not balanced: the airplane is turning while slipping or skidding sideways.
Example Sentence 1
The student rolled into the turn without enough rudder, and the ball slid to the outside — a classic uncoordinated turn.
Example Sentence 2
During the instrument approach the instructor noted the student was making uncoordinated turns and corrected with coordinated aileron and rudder.