Slow Flight

Slow Flight

Objectives

To know:
  • The proper flight technique necessary to achieve precise control of the aircraft while operating within the slow fight speed range.
  • To recognize the symptoms when approaching the slow flight speed range to avoid inadvertent entry.
  • To develop coordination and install confidence in handling the aircraft.

Why ?

  • Recognize slow flight and avoid stalling.
  • We go through slow flight on every flight: takeoff, landing, overshooting.
  • Learn to handle aircraft at slower speeds (mushy controls).
  • Learn recovery technique.

Link:

  • Straight-and-level flight.
  • Flight for maximum endurance.

Review questions

  • Could you explain what is the best endurance ?
  • What is required during flight below the speed for maximum endurance ?
  • Define max endurance.
  • In what flight condition is torque effect the greatest in a single engine ?

Slow Flight Theory

Range of airspeeds between the maximum endurance speed for a particular aircraft and the point just above its stalling speed of the existing flight conditions”.

  • The slowest airspeed at which the airplane is capable of maintaining controlled flight without indications of a stall—usually 3 to 5 knots above stalling speed.
  • Because of the risks of stall, slow flight can be hazardous specially at low altitude.
  • Slow flight should be of short duration because of the insufficient airflow for engine cooling.
  • Stall can happen at any power setting

Before entering in slow flight

1: Altitude:
  • 2000 feet minimum (Must be recovered by 2000′ AGL).
2: Area:
  • No built-up area above.
3: Seat belt:
  • Check (fasten).
4: Cockpit check:
  • Primer locked.
  • Oil gauges check (green)
  • Master switch.
  • Magneto both.
  • Carburetor on
  • Mixture rich.
  • Fuel selector both.
5: look out
                             HASEL
  • HEIGHT (ALTITUDE)
  • AREA (BUILT-UP, AGGLOMERATION, PEOPLE ASSEMBLY…)
  • Security (seat belt fasten, door and windows close)
  • Engine (cockpit check)
  • Look out.

Slow Flight: Entry procedure

  • HASEL
  • Reduce power (Approx. 1600-1700 RPM- check POH)
  • Raise the nose to maintain altitude
  • Increase power to maintain airspeed and altitude
  • Right rudder to counteract slipstream and asymmetric thrust
  • At appropriate speed add flaps 10°, 20°
  • Trim
  • Lookout

Slow Flight Recognition

  • Low airspeed with high power setting.
  • High angle of attack.
  • Stall Horn cutting in and out.
  • The controls will be sluggish and not as responsive as they would be at a higher speed.
  • Important adverse yaw.

During slow flight:

  • Control airspeed with pitch.
  • Control altitude with power.
  • Control the airplane with ailerons and rudder and confirm with heading indicator.
  • Check instrument briefly to confirm what you see outside.
  • This is a visual maneuver, BUT watch the airspeed indicator, and altimeter to stay level and at the correct airspeed.

Slow Flight Recovery

  • Lookout
  • Full power and carburetor heat off
  • Gradually lower the nose
  • flaps 20°, 10°, 0°
  • Reduce power to cruise.
  • Trim
  • Lookout

Slow flight: turn

  • Set heading.
  • 15º Max Bank Angle.
  • Add Power.
  • Add Right Rudder.
  • Add Back Pressure.

Slow Flight: Climb

  • Set heading.
  • Full Power & Right Rudder.
  • Maintain airspeed with pitch.
  • Gentle bank only (if you turn in the same time).

Slow flight: descent

  • Set heading.
  • Reduce Power
  • Reduce Right Rudder.

Slow flight: flaps

  • Flaps increase the camber of the wing and thus the lift.
  • This addition of lift reduce the stall airspeed.
  • Be careful !!!! When power is applied for recovery, the airplane will pitch up unless you maintain positive control of the pitch with the elevator.

Review questions

  • What are the symptoms of slow flight ?
  • When slow flying, why should you be particularly alert , when checking engine temperature gauge ?
  • What is the minimum altutude to perform a slow flight maneuver ?
  • What does the acronym HASEL mean ?
  • What are first 3 steps in the entry to slow flight?