Side-Slip lesson
Slipping is a manoeuvre in which the aircraft is placed in a banked attitude but its tendency to turn is either reduced or prevented by the use of rudder.
Objectives
- Entry, practical use and recovery from different slips.
- Safety considerations.
Why ?
- This technique it’s important for landing with crosswind.
Link
Review Questions
- How do you maintain a coordinated flight ?
- What is the main difference from a spin and spiral?
- If you apply left rudder, which way would the nose of the aircraft point ?
Type of slipping
- Side-Slip (regular slip): used for crosswind landings.
- Forward slip: used to lose extra height. (Needed during flap failure for instance).
- Slipping Turn: used to lose extra height while in a descending turn.
Side-Slip
- Side-slip purpose is to counteract the effect of drift when landing in a cross-wind.
- In a sideslip, the airplane’s longitudinal axis remains parallel to the original flight path.
- The steeper the bank—the greater the degree of slip.
- As bank angle is increased, additional opposite rudder is required to prevent turning.
Side-slip: Entry
- Use ailerons to bank the airplane in the direction of the wind.
- At the same time use opposite rudder to maintain the airplane’s longitudinal axis parallel to the original flight path.
- Use elevator to control approach speed.
- Use power to control rate of descent while on approach to landing.
- The drift is controlled with aileron, and the heading with rudder.
- Anticipate control pressure when maintaining a slip. If full rudder is used, considerable aileron pressure may be needed to maintain the bank.
Side-slip: Recovery
Simultaneously :
- Releasing rudder pressure.
- Leveling the wings.
- Adjusting pitch to resume normal descend and attitude.
Forward-slip
- The forward slip will change the heading (longitudinal axis) of the aircraft away from the down wing, while retaining the original track (flight path over the ground) of the aircraft.
- A forward-slip is useful when a pilot has set up for a landing approach with excessive height or must descend steeply beyond a tree line to touchdown near the start of a short runway.
- Assuming that the runway is properly lined up, the forward slip will allow the aircraft track to be maintained while steepening the descent without adding excessive airspeed.
- Since the heading (or longitudinal axis) is not aligned with the runway, the slip must be removed before touchdown to avoid excessive side loading on the landing gear.
Forward-slip Entry
- Power to idle to increase the rate of descent.
- Roll into a gentle bank into the wind
- At the same time, apply opposite rudder to keep the plane from turning on the lowered wing.
- Pitch: To prevent the airspeed from increasing, raise the nose slightly above the normal gliding position.
Forward-slip Recovery
- Raising the low wing
- In the same time release rudder pressure.
- Level the wing and adjust the pitch attitude.
Slipping Turn
- A slipping turn uses the same procedure as forward slip (increased the rate of descent without increasing airspeed) but does this in turn.
- The turn is slowed, but not prevented, by the use of opposite rudder.
- The slipping turn can be useful during a turn to final approach, especially in the case of a forced landing in which excess altitude must be lost.
- Recovery procedure is identical to forward slip
Instruments
- Turn Coordinator:
- Wings slightly inclined
- Ball indicates opposite to rudder position
- Altimeter and Vertical Speed Indicator:
- High rate of descent
- Attitude indicator:
- Bank in the direction of control column deflection.
*Because of the location of the pitot tube and static vents, airspeed indicators in some airplanes may have considerable error when the airplane is in a slip.
Review Questions
- What’s the procedure for entry and recovery from a side-slip?
- What are the 3 types of slip ?
- In a sideslip, does the airspeed indicator over-read or under-read ?
