Slow Speed Flight

Question 1

DUTCH ROLL

Answer 1

● Dutch Roll is a combination of yaw and roll that causes the aircraft nose to make a figure 8 (side to side) in the air.
● Aircraft designs that increase roll restoring capability such as high wing, dihedral and sweep back, tend to increase the Dutch Roll tendency

● Dutch roll results from the positive lateral stability of the aircraft
being relatively stronger than the positive directional stability.
● Roll around the longitudinal axis induces a sideslip into the
relative wind in the direction of the rolling motion.
● Strong lateral stability tends to restore the aircraft to level flight
while the weaker directional stability attempts to correct the
sideslip.
○ The yaw correction lags behind the roll restoring motion.
● As the aircraft passes through level flight, the yawing motion is
still continuing in the direction of the original roll and now a
sideslip is being introduced in the opposite direction

● High-winged aircraft often are designed with slightly anhedral
wings to counteract the dutch roll.
● Aileron or rudder correcting inputs may increase the Dutch Roll
as the pilot is typically a step behind the correction(s) required.
● Yaw dampers reduce the Dutch Roll tendency considerably as
the accelerometers in the tail will signal the autopilot and yaw
the aircraft much more quickly than a human can react.

• in right yaw, left wing moves faster and rises and plane sideslips towards the right
• when wind hits side of fin, it pushes it towards the right, making plane yaw back left, and the motion becomes like a pendulum

Question 2

SLOW SPEED ROCKING

Answer 2

● At very slow speeds such as just before touchdown, a rocking or rolling motion can be induced in jet aircraft.
● Aileron corrections will usually be one step behind the correction required and will therefore increase the rolling motion.
● In many aircraft types, it is best to correct this with rudder

Question 3

LOW ENERGY REGIME ALL TURBINE POWERED AIRCRAFT

Answer 3

● The low energy regime is defined by Transport Canada as:
○ Flaps and gear are in the landing configuration
○ Aircraft is in descent
○ Thrust has been stabilized in the idle range
○ Airspeed is decreasing
○ Height is 50 feet (depending on landing procedures for the type) or less above runway elevation.
● The decision to place an aircraft in the low energy regime is a decision to land

● Any attempt to commence a go-around or balked landing while in the low energy regime is a high risk, undemonstrated maneuver.