Definition
A landing technique in which the pilot intentionally crosses the controls -- banking the airplane in one direction while applying opposite rudder -- to increase the rate of descent without increasing airspeed. The longitudinal axis of the airplane is held at an angle to the original flightpath, while the ground track is maintained along the runway centerline. It is used to lose excess altitude on final approach when flaps are unavailable or insufficient.
Plain English
A way of dropping height quickly on final approach without speeding up. The pilot tilts the wings one way and pushes the rudder the other way, which makes the airplane fly slightly sideways through the air. This sideways angle creates extra drag, so the airplane comes down faster while still tracking straight toward the runway.
Context Anchor
Used during the final approach to landing when the airplane is higher than desired and the pilot needs to lose altitude without gaining too much speed.
Derivation
"Slip" comes from the airplane's path through the air -- it is no longer flying straight ahead but slipping sideways at an angle. "Forward" distinguishes it from a sideslip: in a forward slip the ground track stays aligned with the runway while the nose points off to one side.
Why Pilots Care
It gives precise, immediate altitude control on final approach without raising airspeed or adding drag devices, which is useful on short fields or when obstacles are present.
Grounding Statement
In a forward slip, the side of the airplane meets more airflow, which creates extra drag and lets the airplane come down faster.
Intuition Check
Do not read “slip” here as an accidental skid or a loss of control. A forward slip to a landing is intentional: the pilot uses crossed controls to add drag, then straightens the airplane before touchdown.
Example Sentence 1
Realizing he was too high on final, the student lowered the upwind wing, applied opposite rudder, and entered a forward slip to lose altitude before the threshold.
Example Sentence 2
After the slip was removed and the airplane realigned with the runway, the landing was completed normally.