Definition
A turn in which the aircraft slides sideways toward the inside of the turn because the rate of turn is too low for the angle of bank. The aircraft is banked too steeply for the amount of rudder being used, so the nose tracks behind the turn and the aircraft drifts toward the low wing.
Plain English
A turn where the aircraft is leaning into the turn more than it is actually turning, so it slides sideways toward the inside of the curve.
Context Anchor
Seen when learning coordinated use of aileron and rudder, especially during turns, instrument scan, and correction for adverse yaw.
Derivation
From 'slip,' meaning to slide sideways. The aircraft is literally sliding toward the inside of the turn rather than carving cleanly through it.
Why Pilots Care
Unintentional slipping turns waste altitude and energy and can mask an impending stall; pilots also use intentional slips to lose altitude quickly or to correct for crosswinds on landing.
Analogy
It is like trying to turn a bicycle while the frame is not lined up with the path of travel. You are still turning, but the motion is not clean and centered.
Intuition Check
Do not read “slipping” as the tires losing grip on the ground. In flight, a slipping turn means the airplane is moving sideways through the air because bank and rudder are not matched.
Example Sentence 1
The instructor pointed out that the ball had rolled to the inside of the turn, indicating a slipping turn, and asked the student to add rudder to coordinate.
Example Sentence 2
During the crosswind landing the instructor used a slipping turn to keep the fuselage aligned with the runway until touchdown.