Definition
Directional changes made by an aircraft while moving on the ground under its own power, typically used to verify that heading-sensitive flight instruments respond correctly before flight. During an instrument system check, taxi turns are used to confirm that the heading indicator, magnetic compass, and turn coordinator move in the proper direction and by the expected amount.
Plain English
Turns the pilot makes while taxiing the aircraft on the ground. They are deliberately used to check that the cockpit instruments showing heading and turn direction are working properly before takeoff.
Context Anchor
Seen during taxiing before takeoff, especially when checking instruments before an instrument flight.
Derivation
Taxi comes from the same root as taxicab, originally from the French taximètre — a meter measuring fare. Aircraft moving slowly on the ground were said to be taxiing, like a cab moving through a city. A taxi turn is simply a directional change made during that ground movement.
Why Pilots Care
Confirms that critical navigation instruments are functioning before entering instrument meteorological conditions.
Intuition Check
Do not read taxi turns as only the turns needed to steer to the runway. In this inspection context, they are also used as a live check that the airplane’s instruments respond correctly while turning on the ground.
Example Sentence 1
During taxi turns, the pilot confirmed that the heading indicator and turn coordinator both responded correctly in the direction of the turn.
Example Sentence 2
During pre-takeoff instrument checks, taxi turns showed normal deflection on the turn coordinator.