Definition
A controlled flight maneuver in which the airplane's longitudinal axis remains aligned with the original flight path, but the airplane is banked into the wind while opposite rudder is applied to prevent turning. The result is a flight path that tracks straight ahead while the airplane moves sideways through the air, increasing drag and steepening the descent without increasing airspeed.
Plain English
A side slip is when the pilot deliberately banks the wings one way and pushes the rudder the other way, so the airplane keeps flying straight ahead but slides slightly sideways through the air. It is used to lose altitude quickly or to stay lined up with the runway in a crosswind.
Context Anchor
Seen during approach and landing, especially when correcting for crosswind drift or adjusting alignment with the runway.
Derivation
From 'side' (sideways motion) and 'slip' (to slide). The airplane is literally slipping sideways through the air rather than flying cleanly forward through it.
Why Pilots Care
Gives precise control over descent rate and runway alignment without gaining excess speed, which is essential on short or obstructed fields and in crosswinds.
Grounding Statement
Picture the airplane’s nose staying pointed down the runway while the airplane moves sideways toward the low wing.
Intuition Check
A side slip is not an uncontrolled skid or a mistake. It is a deliberate control technique: one wing is lowered, and rudder is used to keep the nose from swinging into a turn.
Example Sentence 1
On final approach with a strong left crosswind, the pilot established a side slip by banking into the wind and using right rudder to keep the nose aligned with the runway.
Example Sentence 2
During the crosswind landing the pilot held a sideslip to keep the nose aligned with the runway while the airplane drifted sideways with the wind.