Definition
A rotational force acting on an airplane around its lateral (wing-to-wing) axis that tends to raise the nose and lower the tail. In the context of flap extension, certain flap designs shift the wing's center of lift in a way that produces this nose-up rotation, which the pilot must counter with elevator or trim input.
Plain English
A turning force that wants to push the airplane's nose up and the tail down. When some flaps are lowered, the airplane naturally tries to pitch nose-up until the pilot trims or pushes forward on the controls.
Context Anchor
Encountered when studying flap extension, power changes, trim, and other situations that change the airplane’s pitch behavior.
Derivation
A 'moment' in mechanics is a turning or rotating force around a pivot point — the term comes from Latin momentum, meaning 'movement' or 'impulse to move.' Knowing this helps: a pitching moment isn't a moment in time; it's a force trying to rotate the aircraft about its pitch axis.
Why Pilots Care
Flap extension on many aircraft produces this moment, requiring forward control pressure or nose-down trim to hold the desired attitude.
Grounding Statement
When the forces on the airplane change in a way that makes the nose want to rise, that tendency is a nose-up pitching moment.
Intuition Check
Do not read “moment” as a moment in time. Here it means a turning tendency that raises the airplane’s nose.
Example Sentence 1
Lowering the flaps on this airplane produces a noticeable nose-up pitching moment, so the pilot retrims forward to hold the approach speed.
Example Sentence 2
After flap extension the pilot applied nose-down trim to relieve the nose-up pitching moment and maintain level flight.