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:
Primerlocked.
Oil gauges check (green)
Masterswitch.
Magnetoboth.
Carburetoron
Mixturerich.
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?