Reduce Power
From straight-and-level flight, gradually reduce power from the normal cruise setting. Allow the airplane to begin slowing down while maintaining the desired heading and altitude.
Pre-flight lesson
Advanced maneuvers
Lesson Objective
In this lesson, you will learn how to recognize, enter, maintain and recover from slow flight. You will also learn the HASEL check, how the airplane behaves at low airspeed, and how to maintain precise control during turns, climbs and descents. This lesson builds on the control of attitude and altitude covered in Straight-and-Level Flight .
Why Learn Slow Flight?
Learn to control the airplane safely at low airspeed
Slow flight develops precise control when the airplane is operating close to the lower end of its normal airspeed range. It also helps you recognize the signs that appear as the airplane approaches a stall.
Aircraft Control
Control the airplane at low airspeed
The flight controls become less responsive as airspeed decreases. Slow-flight practice teaches you to make smooth and precise corrections.
Stall Awareness
Recognize the warning signs
Slow flight helps you recognize changes in aircraft attitude, control response and stall warning before an actual stall develops.
Everyday Flying
Slow flight occurs on every flight
The airplane operates at relatively low airspeeds during takeoff, approach, landing and go-around. Good slow-flight skills therefore apply directly to normal flying.
Coordination
Improve rudder and pitch control
Slow flight requires careful coordination, especially when power is high and airspeed is low. It develops better use of pitch, power and rudder.
What Is Slow Flight?
Slow flight is flight in the low-speed range between the airplane's maximum-endurance speed and a speed just above the stall. In this range, the airplane remains under control, but it behaves very differently from normal cruise flight.
Main Idea
The airplane is flying slowly — but it is not stalled
During slow flight, the airplane operates close to the lower limit of its usable airspeed range. The wing is still producing enough lift to maintain flight, but the airplane is closer to the conditions that can produce a stall.
The objective is therefore not simply to fly as slowly as possible. It is to learn how to control the airplane precisely at low airspeed while preventing a stall.
Airspeed
Lower than normal
The airplane is flown at a low airspeed, often close to the minimum speed at which controlled flight can be maintained without stalling.
Attitude
Higher angle of attack
As airspeed decreases, the airplane normally requires a higher angle of attack to produce the lift needed for flight.
Flight Controls
Less responsive
With less airflow over the control surfaces, the controls generally feel softer and corrections may require larger or more deliberate inputs.
Important
Slow flight is not a stall. The wing remains below its critical angle of attack. However, because the airplane is operating close to the stall, an increase in angle of attack, load factor or an inappropriate reduction in power can bring the airplane closer to a stall.
Remember
Slow flight = low airspeed + high angle of attack +
reduced control response — while the airplane remains
under control and above the stall.
Aerodynamics of Slow Flight
As an airplane slows down, less air flows over the wing. To continue producing enough lift, the airplane must normally fly at a higher angle of attack. This changes the relationship between pitch, drag, power and control response.
Main Principle
Lower airspeed requires a higher angle of attack
In level flight, the wing must continue producing enough lift to support the airplane. When airspeed decreases, the pilot normally increases the angle of attack to maintain the required lift.
The slower the airplane flies, the closer the wing moves toward its critical angle of attack. If that critical angle is exceeded, the wing stalls.
Interactive Slow-Flight Power Curve
Move the slider from higher airspeed toward the stall to see why more power is required to maintain altitude in slow flight.
Airspeed
Higher
Power Required
Increasing
Flight Region
Normal flight
Move toward slow flight
Move the slider toward the left. At first, reducing airspeed reduces the power required. After maximum endurance, the relationship reverses.
On the slow-flight side of the curve, flying slower requires more power to maintain altitude because induced drag increases rapidly.
Angle of Attack
Higher than in cruise
The wing must normally operate at a higher angle of attack to produce the lift required at lower airspeed.
Induced Drag
Drag increases
At high angle of attack, induced drag becomes much more important. This is why more power is required to maintain altitude in slow flight.
Control Response
Controls become less effective
Lower airflow over the control surfaces reduces their effectiveness. Larger or more deliberate control inputs may therefore be required.
Power Required
The back side of the power curve
At normal cruise speeds, slowing down generally reduces the power required. But at sufficiently low airspeed, induced drag becomes so large that this relationship reverses.
In this region, flying even slower requires more power to maintain altitude. This is often called the back side of the power curve or the region of reversed command.
In Practice
During slow flight, small pitch changes can produce noticeable changes in airspeed and angle of attack, while power changes are commonly used to help maintain the desired flight path and altitude. Use the technique recommended for your airplane and by your instructor.
Remember
Lower airspeed → higher angle of attack → more induced drag →
more power required to maintain altitude.
HASEL Check Before Slow Flight
Before entering slow flight, make sure the airplane is at a safe altitude, in a suitable practice area, properly secured, and clear of other traffic. The HASEL check is a simple way to organize these important pre-maneuver checks.
H
Height
Make sure there is enough altitude to perform the exercise safely and recover if an inadvertent stall occurs.
A
Area
Choose a suitable practice area and consider terrain, obstacles, populated areas, airspace and possible emergency landing areas.
S
Security
Check seat belts, doors and windows, and make sure loose objects are secured before beginning the maneuver.
E
Engine
Check engine indications and complete the appropriate aircraft checks according to the checklist and POH/AFM.
L
Lookout
Clear the area carefully for other traffic before beginning the maneuver and maintain an effective visual scan throughout the exercise.
Typical Engine Check
Example for a typical carbureted training airplane
The exact engine check depends on the airplane, but a typical check before slow-flight practice may include:
Primer
Locked
Oil gauges
Check / Green
Master switch
On
Ignition / Magnetos
Both
Carburetor heat
As Required
Mixture
Rich / As Required
Fuel selector
Both, if applicable
Always use the checklist and POH/AFM for the specific airplane. Not every airplane has the same fuel selector, carburetor system, mixture procedure or engine controls.
Why It Matters
Slow flight leaves less margin for error
During slow flight, the airplane operates at low airspeed and a relatively high angle of attack. This means the airplane is closer to the conditions that can produce a stall.
Starting the maneuver with enough altitude, a clear practice area and a proper lookout gives the pilot the time and space needed to respond safely if something does not go as planned.
Aircraft-Specific
Do not memorize one generic engine or cockpit checklist for every airplane. Fuel selection, mixture, carburetor heat, propeller controls and other items vary between aircraft. Follow the POH/AFM, aircraft checklist and your instructor's procedure.
Remember
HASEL = Height • Area • Security • Engine • Lookout
How to Enter Slow Flight — Step by Step
Once the pre-maneuver checks are complete, enter slow flight gradually. The objective is to reduce airspeed while maintaining altitude and coordinated flight, then stabilize the airplane at the desired slow-flight speed.
Reduce Power
→
Maintain Altitude
→
Configure
→
Add Power
→
Trim & Stabilize
1
2
Increase Pitch to Maintain Altitude
As airspeed decreases, gradually increase the pitch attitude as necessary to prevent the airplane from descending. The angle of attack increases as the airplane slows.
3
Configure the Airplane
If the exercise is being performed in a landing, takeoff or other configuration, extend flaps or landing gear as appropriate and only within the applicable operating limitations.
4
Add Power as the Airplane Approaches Slow Flight
As the airplane approaches the desired slow-flight speed, increase power as necessary to maintain altitude. At this low airspeed, induced drag is high, so considerable power may be needed even though the airplane is flying slowly.
5
Maintain Coordination and Trim
Use rudder as required to keep the airplane coordinated as power and angle of attack increase. Once the desired airspeed, altitude and attitude are established, trim the airplane to reduce unnecessary control pressure.
Target Airspeed
Stabilize just above the stall
The exact target speed depends on the airplane, configuration and training objective. In typical slow-flight training, the airplane is stabilized at a speed just above the stall warning or stall condition for the selected configuration.
Use the POH/AFM and your instructor's procedure rather than memorizing one airspeed for every airplane.
Cessna 172 Training Note
In a Cessna 172, the exact power setting, flap configuration and target airspeed can vary between models and training procedures. Do not treat a single RPM or airspeed value as universal. Use the POH for the specific aircraft and follow your instructor's technique.
Remember
Reduce power → maintain altitude as the airplane slows →
configure as required → add power to maintain altitude →
coordinate, trim and stabilize.
How to Recognize and Maintain Slow Flight
Once the airplane is established in slow flight, do not rely on the airspeed indicator alone. Learn to recognize the airplane's attitude, control feel, sound and coordination, while using outside references and the flight instruments to maintain precise control.
Recognition
What does slow flight feel like?
Slow flight feels noticeably different from normal cruise. The airplane is operating at low airspeed and a relatively high angle of attack, so the controls are less responsive and the airplane requires more deliberate control inputs.
With practice, these changes become important visual, physical and audible cues that help you recognize when the airplane is approaching the slow-flight range.
Airspeed
Low and stable
The airspeed is much lower than in normal cruise. Use the indicator as part of your scan, but avoid staring continuously at it.
Attitude
Higher angle of attack
The airplane normally flies with a noticeably higher angle of attack than during normal cruise flight.
Control Feel
Softer and less responsive
Lower airflow over the control surfaces makes the controls feel less effective. Corrections may require larger or more deliberate inputs.
Sound
Airflow sounds different
As airspeed decreases, the sound of the airflow around the airplane changes. This is another useful cue that the airplane is slowing down.
Power
Relatively high for the airspeed
Even though the airplane is moving slowly, substantial power may be required to overcome induced drag and maintain altitude.
Coordination
More rudder may be required
In a propeller-driven airplane, high power at low airspeed can increase yawing tendencies. Use rudder as required to remain coordinated.
Maintaining Slow Flight
Use pitch and power together
Once the desired slow-flight condition is established, make small, smooth corrections. In stabilized slow flight, small pitch changes have a strong effect on airspeed, while power changes have a strong effect on altitude and flight path.
These controls are not completely independent. Changing pitch also affects altitude, and changing power can affect airspeed and pitch attitude. Think of pitch and power as a coordinated pair, not as two completely separate controls.
If Airspeed Changes
Make a small pitch correction
Correct the pitch smoothly, then allow the airplane time to respond before making another adjustment. Avoid chasing the airspeed indicator.
If Altitude Changes
Adjust power as required
Use an appropriate power correction to regain or maintain the desired altitude, while coordinating pitch as necessary.
If the Airplane Yaws
Maintain coordination
Apply the rudder needed to keep the airplane coordinated. Avoid using excessive aileron or making abrupt control inputs at low airspeed.
Keep Looking Outside
Slow flight is a visual maneuver. Maintain awareness of the horizon and outside references, then make brief instrument checks for airspeed, altitude, heading and coordination. Do not allow the instrument panel to become your only reference.
Stall Awareness
Stay below the critical angle of attack
Slow flight places the airplane closer to the stall, but slow flight is not a stall. Maintain precise control and avoid abrupt pitch or control inputs that could increase the angle of attack beyond its critical value.
Depending on the airplane and the training target, you may be operating close to the activation point of the stall-warning system. Do not use the warning device as the primary method of controlling slow flight.
Trim
Once the airplane is stabilized, use trim to relieve continuous control pressure. Trim helps you make precise corrections, but it does not replace active control of pitch, power and coordination.
Remember
Look outside • make small pitch and power corrections •
stay coordinated • cross-check the instruments •
avoid abrupt control inputs.
How to Exit Slow Flight
To exit slow flight, smoothly transition the airplane back toward normal flight while maintaining altitude and coordinated control. As power is increased and the airplane accelerates, control the pitch attitude to reduce the angle of attack, then return the airplane progressively to its normal configuration.
Add Power + Control Pitch
→
Maintain Altitude
→
Maintain Coordination
→
Clean Up
→
Trim & Stabilize
1
Add Power and Control the Pitch
Smoothly increase power to begin accelerating out of slow flight. As airspeed and lift increase, apply the forward elevator pressure needed to reduce the angle of attack and maintain altitude.
2
Prevent an Excessive Nose-Up Pitch
The airplane may be trimmed for a high-angle-of-attack, low-speed condition. When power is added and airspeed increases, the airplane may develop a noticeable nose-up tendency. Maintain the required forward control pressure and do not allow the nose to rise excessively.
3
Maintain Altitude and Coordination
Continue adjusting pitch as the airplane accelerates so that altitude remains controlled. Use rudder as required to maintain coordinated flight, particularly as power changes in a single-engine propeller airplane.
4
Retract Flaps and Landing Gear as Airspeed Increases
If flaps or landing gear were extended, return the airplane progressively toward its normal configuration as airspeed increases. Follow the POH/AFM and aircraft procedures for the correct sequence and operating limitations.
5
Retrim and Stabilize
Continue holding the required control pressure while the airplane accelerates. Once the desired airspeed, pitch attitude and power setting are established, retrim for the new flight condition and stabilize the airplane.
Trim & Pitch
Hold the attitude first — then retrim
During slow flight, the airplane may be trimmed to relieve the back pressure needed for the higher angle of attack. That trim setting does not automatically become appropriate when power is added and the airplane accelerates.
Maintain the required forward elevator pressure while the flight condition changes, then retrim progressively once the desired attitude and airspeed are established.
Configuration Change
Anticipate the effect of retracting flaps
Flap retraction changes both lift and drag. Retracting flaps while the airplane is still at very low airspeed can require an immediate change in pitch control to maintain the desired angle of attack and flight path.
Allow the airplane to accelerate and retract the configuration progressively according to the procedure for the aircraft you are flying.
Anticipate the Power Change
In a single-engine propeller airplane, increasing power can produce both pitch and yaw changes. Anticipate these tendencies and use coordinated elevator and rudder inputs while the airplane accelerates.
Important
Do not allow the angle of attack to increase during the exit
Increasing airspeed does not by itself protect the airplane from a stall. An airplane stalls when the critical angle of attack is exceeded, regardless of the indicated airspeed.
During the transition out of slow flight, control the nose attitude as power and airspeed increase. If an actual stall occurs, use the appropriate stall-recovery procedure for the airplane.
Remember
Add power while controlling pitch → apply forward pressure
as airspeed and lift increase → maintain altitude and
coordination → clean up as airspeed increases → retrim
and stabilize.
Flaps and Aircraft Configuration in Slow Flight
Slow flight can be practiced with different flap settings. Changing the flap configuration changes the airplane's lift, drag, pitch attitude, stall speed and trim, so each configuration requires slightly different control inputs.
Clean Configuration
Flaps retracted
With the flaps retracted, drag is lower and the airplane generally has a higher stall speed than it does with flaps extended.
Partial Flaps
Some flap extension
Lift and drag increase, and the airplane may require a different pitch attitude, power setting and trim to maintain slow flight.
Full Flaps
Maximum approved flap setting
Drag is substantially higher and the airplane can typically operate at a lower airspeed before reaching the stall than in the clean configuration.
What changes when the flaps are extended?
Extending flaps changes the shape and camber of the wing. On most training airplanes, this increases both lift and drag and reduces the stall speed for that configuration.
The airplane may also experience a noticeable pitch change when the flaps move. The direction and amount of that pitch change depend on the aircraft design and flap system.
Because drag increases, more power may be required to maintain altitude at the same low airspeed. Once the new configuration is stabilized, retrim the airplane as required.
Lift
Increases
Drag
Increases
Stall Speed
Usually decreases
Pitch / Trim
Changes with configuration
Extending Flaps
Anticipate the change instead of reacting to it
When flaps are extended during slow flight, both lift and drag change. The airplane may change pitch attitude and begin to accelerate or decelerate unless the pilot adjusts pitch and power.
Make configuration changes progressively, anticipate the aerodynamic response, and stabilize the airplane before making another major change.
Retracting Flaps
Do not retract the flaps abruptly at very low airspeed
Retracting flaps removes some of the additional lift they were providing. If the airplane is still flying very slowly, abrupt flap retraction can produce a significant loss of lift and reduce the margin from the stall.
Control the pitch
→
Allow airspeed to increase
→
Retract progressively
→
Retrim
Flap Limitations
Always respect the aircraft's flap operating limitations. Extend or retract the flaps only within the permitted airspeed range and use the flap settings and sequence specified in the POH/AFM.
Training Purpose
Practice different flap configurations
Slow flight with the flaps retracted does not feel exactly like slow flight with partial or full flaps. Practicing different configurations helps you recognize how control response, pitch attitude, stall speed and power requirements change.
These differences are directly relevant to normal flying because the airplane routinely operates at low airspeeds and changing flap settings during takeoff, approach, landing and go-around.
Remember
Flaps change lift, drag, stall speed, pitch and trim •
anticipate each configuration change • protect the airspeed •
extend and retract flaps according to the POH/AFM.
Turns, Climbs and Descents in Slow Flight
Once straight-and-level slow flight is stable, the next step is to maneuver while keeping the airplane coordinated and safely above the stall. Turns, climbs and descents require different combinations of pitch, power and rudder, but all control inputs should remain smooth and deliberate.
01
Slow-Flight Turn
Turn smoothly and protect the stall margin
Enter the turn with smooth, coordinated aileron and rudder inputs. Because part of the total lift is now directed horizontally to produce the turn, more total lift is required if altitude is to remain constant.
In slow flight, avoid trying to hold altitude by simply pulling farther back on the elevator. Excessive back pressure increases the angle of attack and reduces the margin from the stall.
02
Slow-Flight Climb
Add power without losing airspeed control
To begin a climb while remaining in slow flight, smoothly increase power and adjust pitch as necessary to maintain the desired slow-flight airspeed.
Do not attempt to increase the climb rate simply by raising the nose. Increasing pitch without sufficient power increases the angle of attack and can move the wing closer to its critical angle of attack.
In a single-engine propeller airplane, the higher power setting can also increase yawing tendencies, so anticipate the need for additional rudder.
03
Slow-Flight Descent
Reduce power while protecting the airspeed
To establish a descent from stabilized slow flight, smoothly reduce power and adjust pitch as required to maintain the desired airspeed.
The airplane should be allowed to descend rather than allowing the airspeed to decay. Continue monitoring coordination and angle of attack throughout the descent.
Remember that descending does not automatically move the airplane farther from a stall. A stall still occurs whenever the critical angle of attack is exceeded.
Stall Margin
Bank angle matters
In a level turn, increasing bank increases load factor. The wing must produce more lift, which requires a higher angle of attack and increases stall speed. Avoid aggressive bank and abrupt elevator inputs during slow flight.
Coordination
Keep yaw under control
Maintain coordinated flight during turns, climbs and descents. At low airspeed, excessive yaw combined with a high angle of attack can create the conditions for a stall-and-spin entry.
Remember
Turn: smooth bank + coordination + power as required •
Climb: increase power and maintain airspeed with pitch •
Descent: reduce power and protect the airspeed.
Safety and Common Errors in Slow Flight
Slow flight requires precise control because the airplane is operating at low airspeed and relatively close to the critical angle of attack. The safest technique is to remain coordinated, attentive and smooth, and to correct small deviations before they become large ones.
Priority 01
Look outside
Maintain an effective traffic scan and awareness of the horizon. Instruments support the maneuver — they should not become your only reference.
Priority 02
Stay coordinated
Use rudder as required to prevent unwanted yaw, particularly when operating at high power and low airspeed.
Priority 03
Protect the angle of attack
Avoid abrupt pitch or control inputs. Slow flight can quickly become a stall if the critical angle of attack is exceeded.
Common Errors
Recognize the error — then correct the cause
Most slow-flight problems come from a small number of recurring habits: poor pitch control, inadequate coordination, fixation inside the cockpit, incorrect power management, or failing to anticipate a configuration change.
Instead of simply correcting the resulting altitude or airspeed deviation, identify what caused it and make a smooth, measured correction.
Pitch Control
During the entry
Common Error
Not enough back pressure
As power is reduced, the airplane begins to descend instead of maintaining altitude.
Better Habit
Anticipate the loss of airspeed
Increase pitch progressively as the airplane slows and use outside attitude references to maintain altitude.
Common Error
Too much back pressure
The airplane climbs while airspeed decreases rapidly, moving closer to the stall.
Better Habit
Make small pitch changes
Establish the attitude progressively and allow the airplane time to respond instead of making one large elevator input.
Coordination
Power and rudder
Common Error
Insufficient rudder
High power and low airspeed can produce significant yaw in a propeller-driven airplane.
Better Habit
Coordinate every power change
Anticipate the yawing tendency and use rudder as required rather than waiting for the airplane to become uncoordinated.
Common Error
Poor power management
Too little or too much power results in unwanted altitude, airspeed or flight-path changes.
Better Habit
Make measured power corrections
Adjust power smoothly, coordinate the resulting pitch and rudder changes, and allow the airplane to stabilize.
Awareness
Eyes and attention
Common Error
Fixating on the instruments
Staring at the airspeed indicator or another instrument reduces traffic awareness and often leads to chasing small indications.
Better Habit
Look outside, then cross-check
Use the horizon and airplane attitude as primary references, with short instrument checks to confirm performance.
Common Error
Poor division of attention
Concentrating on one task can allow heading, altitude, coordination or traffic awareness to deteriorate.
Better Habit
Keep a continuous scan
Divide attention between outside references, aircraft control, instruments and traffic rather than completing each task in isolation.
Configuration
Flaps and trim
Common Error
Not anticipating flap effects
Extending or retracting flaps changes lift, drag, pitch and angle of attack. An abrupt change can destabilize the airplane.
Better Habit
Anticipate before moving the flaps
Make configuration changes progressively, control pitch and airspeed, then stabilize before continuing.
Common Error
Improper trim
Flying with excessive control pressure makes precise slow-flight control more difficult and increases workload.
Better Habit
Establish attitude first, then trim
Use the flight controls to establish the desired condition, then trim to relieve continuous control pressure.
Stall Warning
Do not ignore a stall indication
If a stall warning, aerodynamic buffet or another stall cue occurs during normal slow-flight practice, respond promptly by reducing the angle of attack and adjusting power as necessary while maintaining coordinated flight. Do not continue pulling back simply to maintain altitude.
One Error Begins Before the Maneuver
Failure to adequately clear the area is one of the FAA's listed common slow-flight errors. Complete the appropriate lookout before entry and continue scanning for traffic throughout the maneuver.
Remember
Look outside • stay coordinated • use smooth pitch and
power corrections • anticipate flap changes • trim properly •
respond immediately to any stall indication.
Slow Flight Review Questions
Before moving on, check that you understand the key ideas behind slow flight. Try to answer each question before opening the answer.
8
These questions cover the main concepts from this lesson: aerodynamics, HASEL, entry and exit, flap configuration, maneuvering and stall awareness.
01
Aerodynamics
Why can maintaining altitude require more power as the airplane becomes very slow?
Show Answer
Induced drag increases.
At low airspeed, the airplane needs a higher angle of attack to produce the required lift. This increases induced drag, so more power may be required to maintain altitude.
02
HASEL
What does HASEL help you check before practicing slow flight?
Show Answer
Height • Area • Security • Engine • Lookout
HASEL organizes the important checks before beginning the maneuver, including sufficient altitude, a suitable area, a secure cockpit, engine checks and traffic lookout.
03
Entry
As power is reduced during the entry, what should you do to prevent the airplane from descending?
Show Answer
Increase pitch progressively.
As airspeed decreases, increase pitch as required to maintain altitude. Then add power as necessary as the airplane approaches the desired slow-flight condition.
04
Exit
Why must pitch be controlled while power is increased during the exit from slow flight?
Show Answer
To prevent an excessive nose-up tendency.
The airplane may be trimmed for a high-angle-of-attack condition. As power, airspeed and lift increase, apply the required forward elevator pressure to reduce angle of attack and maintain altitude.
05
Flaps
What are the main aerodynamic effects of extending the flaps?
Show Answer
More lift and more drag.
Flap extension also changes pitch and trim, and typically lowers the stall speed for the selected configuration.
06
Turns
Why should aggressive bank and excessive back pressure be avoided during slow flight?
Show Answer
They reduce the stall margin.
Increasing bank in a level turn increases load factor and stall speed. Excessive back pressure also increases angle of attack, moving the wing closer to the stall.
07
Coordination
Why is rudder control especially important at low airspeed and high power?
Show Answer
Propeller-related yawing tendencies become more noticeable.
Use rudder as required to keep the airplane coordinated. Excessive yaw combined with a high angle of attack can create conditions for a stall-and-spin entry.
08
Stall Awareness
Does an airplane stall because it reaches a specific indicated airspeed?
Show Answer
No.
A wing stalls when it exceeds its critical angle of attack. The indicated airspeed at which that occurs can change with load factor, configuration and other flight conditions.
Ready to Continue?
You should be able to explain not only what control input to make, but also why the airplane responds that way. If one of these answers is unclear, revisit the corresponding section before continuing.
Further Training
Continue Your Training with Pilot Institute
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