Definition
The vertical pointer on a turn-and-slip indicator that shows the rate at which the airplane is turning around its vertical axis. When the needle is deflected to one side of center, the airplane is turning in that direction; the further the deflection, the higher the rate of turn. A standard-rate turn (3 degrees per second) is shown by the needle aligned with the standard-rate index mark, often called a 'one-needle-width' deflection on older instruments.
Plain English
A small pointer on one of the cockpit instruments that swings left or right to show which way the airplane is turning and how fast it is turning.
Context Anchor
Seen on older turn-and-slip instruments and in spin awareness discussions, where it can help confirm the direction the airplane is rotating.
Derivation
“Needle” comes from the use of a thin pointer on older mechanical instruments. In this term, it does not mean a sewing needle; it means the moving pointer on the cockpit instrument.
Why Pilots Care
It reveals uncoordinated flight or spin rotation direction when visual references are lost, guiding correct rudder input for recovery.
Intuition Check
Do not read “turn needle” as a separate control or part of the airplane outside the panel. It is an instrument pointer that shows turn direction and rate.
Example Sentence 1
In a fully developed spin, the turn needle was pegged to the left, confirming the direction of rotation.
Example Sentence 2
In the cockpit, the pilot confirmed spin direction by noting which way the turn needle was displaced before initiating recovery.