The forward slip to a landing
Flying sideways on purpose: how a slip trades altitude without airspeed, why it is slipped into the wind, what the airspeed indicator does during it, and the fuel and flap limitations that go with it.
13 min read · Flight maneuvers
After this lesson you can
- Explain what a slip is aerodynamically, and why a forward slip loses altitude without gaining airspeed.
- Distinguish the forward slip from the sideslip, and say what each is for.
- Enter, hold, adjust and discontinue a forward slip on final, including the wind correction that goes with it.
- Name the airplane limitations on slips and the reason for each.
- Recognize the airspeed indication errors in a slip and fly the maneuver by attitude, sound and feel.
A slip occurs when the bank angle of an airplane is too steep for the existing rate of turn. Unintentional slips are the result of uncoordinated rudder and aileron. Intentional slips are used to dissipate altitude without increasing airspeed, or to adjust the ground track during a crosswind, and the Airplane Flying Handbook explains why the private pilot standards include one: in a real engine failure, a pilot may initiate a descent using a forward slip much more quickly than by deploying flaps, and can remove the slip without penalty, whereas retracting flaps on an approach could lead to an unwanted loss of altitude.
Some pilots avoid the maneuver because the sideways force on the occupants feels uncomfortable and a flap approach feels more familiar. That is the reason it is tested.
The rest of this lesson
- 1.What a slip is, and why it descends without accelerating
- 2.Flying it: entry, wind correction, the practical limit, and the exit
- 3.The limitations: fuel, flaps, time, and the tail
These 3 sections, their figures, the checks along the way and the end-of-lesson quiz come with the PPL track. Paid once, yours for good.
Key terms
Try to recall each definition before turning the card.