Definition
A force acting on the airplane that tends to rotate it about its vertical axis, causing the nose to swing left or right. In a climb, the most common source is the left-turning tendencies produced by engine power, particularly torque, P-factor, slipstream, and gyroscopic precession.
Plain English
A push that tries to swing the airplane's nose sideways — to the left or right — rather than up, down, or rolling.
Context Anchor
Seen when discussing how power changes, climbs, and rudder use affect the airplane’s tendency to turn its nose left or right.
Derivation
Yaw' is an old nautical term for a ship swinging off its intended heading. 'Moment' in physics means a turning force around a point or axis. Together, a yawing moment is simply a turning force around the airplane's vertical axis.
Why Pilots Care
Uncorrected yawing moments cause the airplane to drift off heading and can produce uncoordinated flight, especially at high power settings in climbs.
Intuition Check
Do not read moment as a point in time here. In this context, moment means a turning effect that tries to rotate the airplane.
Example Sentence 1
As the pilot advanced the throttle for the climb, the left-turning yawing moment from the propeller required steady right rudder to keep the nose tracking straight ahead.
Example Sentence 2
When entering a climbing turn to the left, the existing yawing moment from the propeller assists the turn.