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?