Definition
A controlled flight maneuver in which the airplane is intentionally flown with crossed controls — aileron deflection in one direction and opposite rudder — so that the airplane moves through the air partially sideways. This increases drag and steepens the descent angle without increasing airspeed, allowing the pilot to lose altitude quickly while maintaining a desired ground track or alignment with a runway.
Plain English
Deliberately flying the airplane slightly sideways through the air to come down faster without speeding up. The pilot does this by banking one way and pressing opposite rudder at the same time.
Context Anchor
Used during approaches, including emergency landing approaches, when the airplane is too high or when a crosswind must be handled near landing.
Derivation
The word slip describes the airplane sliding sideways through the air rather than moving cleanly forward. The aircraft is no longer aligned with its direction of travel, so it 'slips' through the air, dragging more and descending faster.
Why Pilots Care
It lets a pilot lose excess altitude quickly in an emergency without exceeding safe speeds or risking an overshoot.
Grounding Statement
Picture being high on final approach and using a controlled sideways attitude to increase drag so the airplane comes down more steeply without rushing forward.
Intuition Check
Slipping the airplane does not mean the airplane is out of control or skidding on a surface. Here it means a deliberate, controlled sideways movement through the air, made with bank and opposite rudder.
Example Sentence 1
Realizing he was high on final after the engine quit, the pilot slipped the airplane to lose altitude and touched down within the first third of the field.
Example Sentence 2
During the simulated engine-out exercise the student used slipping the airplane to stay within gliding distance of the chosen field.