Definition
Gyroscopic flight instruments that show the rate at which the aircraft is turning about its vertical axis. The two common types are the turn-and-slip indicator (which uses a needle) and the turn coordinator (which uses a small symbolic aircraft). Both also include an inclinometer -- a curved tube with a ball -- that shows whether the turn is coordinated, slipping, or skidding.
Plain English
Cockpit instruments that tell the pilot how fast the aircraft is turning and whether the turn is being flown smoothly. The needle or miniature aircraft shows the turn; the ball below it shows if the turn is balanced.
Context Anchor
Seen on the instrument panel and used during instrument flying, especially when the pilot cannot rely on the outside horizon.
Why Pilots Care
They enable pilots to maintain coordinated, controlled turns when outside visual references are unavailable.
Intuition Check
Do not assume turn indicators simply show where the airplane is pointed. They show turning motion, and with the ball they help show whether the airplane is turning cleanly or sliding sideways.
Example Sentence 1
After losing the heading indicator in cloud, the pilot used the turn indicator to hold a steady standard-rate turn back toward clearer weather.
Example Sentence 2
An uncoordinated turn was corrected when the pilot noticed the ball displaced on the turn indicator.