Definition
Banking is the act of rolling an aircraft about its longitudinal axis so that one wing is lower than the other, tilting the lift vector sideways to produce a horizontal force component that turns the aircraft.
Plain English
Tipping the aircraft sideways so one wing drops and the other rises. This sideways tilt is what makes the aircraft turn.
Context Anchor
Used when discussing turns, especially instrument turns where the pilot controls the tilt by reference to the flight instruments instead of the outside horizon.
Derivation
From the older sense of 'bank' meaning a sloped or tilted surface, like the banked edge of a road or racetrack curve. An aircraft in a turn tilts in the same way a banked road tilts inward.
Why Pilots Care
Correct banking produces coordinated turns, prevents slips or skids, controls load factor, and keeps the aircraft within its performance limits while changing direction.
Intuition Check
Banking is not just the airplane changing heading. Banking is the sideways tilt of the wings that helps the airplane turn.
Example Sentence 1
She began banking to the left to start the turn toward the next waypoint.
Example Sentence 2
On the back-course approach the instructor emphasized keeping the bank angle constant so the aircraft would not overshoot the final approach course.