Definition
The combined effect of four aerodynamic and mechanical forces that cause a single-engine propeller airplane (with a propeller turning clockwise as viewed from the cockpit) to yaw to the left, particularly during high-power, low-airspeed, high-angle-of-attack flight conditions such as takeoff and climb. The four contributing factors are torque reaction, P-factor (asymmetric propeller loading), spiraling slipstream, and gyroscopic precession.
Plain English
When you apply full power on takeoff or climb, the airplane wants to turn or yaw to the left on its own. You have to push right rudder to keep it pointed straight down the runway.
Context Anchor
Encountered during the takeoff roll, liftoff, and initial climb when the airplane is at high power and still relatively slow.
Why Pilots Care
If left uncorrected, the airplane will drift left of the runway centerline, risking loss of directional control or a runway excursion.
Grounding Statement
Picture adding full power for takeoff and seeing the nose start to move left even though the runway is straight ahead.
Intuition Check
Do not read this as a planned left turn. It means the airplane has a built-in tendency to move left unless the pilot corrects it.
Example Sentence 1
As the throttle came up for takeoff, the student felt the left turning tendency pull the nose toward the left edge of the runway and applied right rudder to keep the airplane tracking the centerline.
Example Sentence 2
During the initial climb after liftoff, reducing power lessened the left turning tendency and allowed smoother rudder inputs.