Definition
The greatest value of the lift coefficient (CL) that a wing can produce before the airflow separates and the wing stalls. It occurs at the critical angle of attack and represents the upper limit of lift the wing can generate at a given configuration.
Plain English
It's the most lift a wing can produce before it stalls. Push the wing past this point and it stops flying, no matter how fast you're going or how heavy the airplane is.
Context Anchor
Seen in stall discussions, performance explanations, and training that explains why an airplane can stall at different speeds but at the same critical wing angle.
Derivation
Coefficient' comes from Latin roots meaning 'working together' -- here it's a number that combines several effects (wing shape, angle of attack, air conditions) into one value representing how efficiently the wing produces lift. 'Maximum' simply marks the peak of that value before stall.
Why Pilots Care
It sets the lowest safe airspeed for a given weight and configuration, directly affecting stall avoidance and recovery.
Grounding Statement
Imagine slowly raising the nose in level flight. The wing produces more and more lift until, at one specific angle, it suddenly can't produce any more -- that peak is the maximum coefficient of lift.
Intuition Check
Do not read this as “the heaviest load the airplane can lift.” It means the highest lift-producing value the wing can reach before the stall begins.
Example Sentence 1
When the wing reaches its maximum coefficient of lift, any further increase in angle of attack causes the airflow to separate and the wing stalls.
Example Sentence 2
Flaps increase the maximum coefficient of lift, allowing the airplane to fly slower during the approach and landing.