What Is a Stall?

An aircraft stall is not an engine failure. It is an aerodynamic condition in which a wing exceeds its critical angle of attack and can no longer maintain its normal pattern of airflow and lift.

That distinction matters because an airplane can stall with the engine producing full power, at a surprisingly high airspeed, or even with its nose pointed below the horizon. Low speed is commonly associated with stalls, but speed alone does not cause one.

Stalls are especially dangerous near the ground, where there may be little altitude available for recovery. Understanding how they develop, how pilots recognise them, and why reducing angle of attack is the essential recovery action is therefore a fundamental part of flight training.

This guide explains the general principles. Pilots must follow the procedures and limitations published for the specific aircraft they fly and practise stall recognition and recovery with a qualified instructor.

What Is an Aircraft Stall?#

A stall occurs when a wing exceeds its critical angle of attack.

The angle of attack is the angle between the wing's chord line and the relative airflow. As angle of attack increases, the wing generally produces more lift until it reaches a maximum useful value.

Beyond the critical angle, airflow separation over the wing increases substantially. The wing's lift coefficient decreases, drag rises, and the airplane may experience a nose drop, wing drop, buffet, loss of control effectiveness, or some combination of these effects.

A stall does not necessarily mean that the wing produces no lift. A stalled wing may continue producing a considerable aerodynamic force. The important change is that increasing angle of attack no longer produces the expected increase in lift, and the wing's performance and controllability deteriorate.

The exact behaviour depends on the aircraft's:

• Wing and airfoil design
• Weight and centre-of-gravity position
• Flap and landing-gear configuration
• Power setting
• Control inputs
• Surface contamination
• Yaw and sideslip
• Rate at which the stall develops

Some wings approach the stall progressively and provide clear warning. Others can lose lift more abruptly.

For the broader aerodynamic background, see How Airplanes Fly.

The Critical Angle of Attack#

The critical angle of attack is the angle at which a particular wing or airfoil reaches its maximum lift coefficient and begins to stall.

It is sometimes described as a single fixed angle, but that needs context. The critical angle depends on the wing's shape and condition. Extending high-lift devices, accumulating ice, or otherwise changing the wing can alter its aerodynamic characteristics.

Many conventional airfoils reach their critical angle somewhere in the mid-to-high teens, but pilots do not use one universal angle as an operational limit. The correct value and the aircraft's behaviour near it are design-specific.

Angle of attack is not pitch attitude#

Pitch attitude describes where the airplane's nose points relative to the horizon.

Angle of attack describes how the wing meets the relative airflow.

They are not the same measurement.

An airplane can have:

• A high nose attitude and a relatively modest angle of attack during a steep climb
• A low or nose-down attitude and a dangerously high angle of attack during an abrupt pull-up or upset
• A nearly level attitude and a high angle of attack during slow flight
• A high airspeed and still exceed the critical angle during an aggressive manoeuvre

Looking at the nose alone therefore cannot tell a pilot whether the wing is close to stalling.

A stall can occur at any airspeed#

A wing stalls because it exceeds its critical angle of attack, not because the airspeed indicator reaches one magical number.

Low airspeed makes a stall more likely in ordinary flight because the wing must operate at a higher lift coefficient to support the airplane's weight. The pilot generally increases angle of attack as speed decreases.

But increased load factor, turbulence, abrupt control inputs, or manoeuvring can bring the wing to its critical angle at much higher speeds.

The cause is excessive angle of attack. Airspeed is one of several conditions that influence when that angle is reached.

What Happens to the Airflow?#

At ordinary angles of attack, airflow follows much of the wing's contour and creates a pressure distribution that produces lift.

As angle of attack rises, the pressure recovery over the upper surface becomes more difficult for the thin layer of air next to the wing, called the boundary layer. Parts of the airflow begin separating from the surface.

Separation does not always spread in exactly the same way.

Depending on the wing design, it may:

• Begin near the trailing edge and move forward
• Begin more abruptly near the leading edge
• Develop first near the wing root
• Develop first or more severely near one wingtip
• Affect one wing more than the other because of yaw, contamination, or control inputs

Many training airplanes are designed so that the wing roots tend to stall before the tips. This helps preserve some airflow over the ailerons and can provide more manageable stall behaviour.

That outcome is not guaranteed in every aircraft or every situation.

Why one wing may drop#

If one wing reaches a greater angle of attack or stalls more deeply than the other, it produces a different combination of lift and drag.

The resulting imbalance can make the airplane roll and yaw toward the more deeply stalled wing.

Applying large aileron inputs before reducing angle of attack can sometimes worsen the situation. A downward-deflected aileron increases the local angle of attack and drag on part of the wing, potentially deepening that wing's stall.

The first priority is therefore to reduce angle of attack. Once the wing is recovering, the pilot can use coordinated controls to level the wings.

Stall Speed Is Not One Permanent Number#

An aircraft's operating handbook publishes stall speeds for specified configurations and conditions. Common examples include:

• VS0, the stall speed or minimum steady speed in the landing configuration
• VS1, the stall speed or minimum steady speed in another specified configuration

These values are useful, but they do not describe every situation in which the airplane can stall.

A published one-G stall speed generally assumes conditions such as:

• Unaccelerated flight
• Coordinated flight
• A specified aircraft weight
• A specified centre-of-gravity position
• A particular flap and gear configuration
• A clean, uncontaminated wing

Change those conditions and the airspeed at which the critical angle is reached can change too.

Weight#

A heavier airplane requires more lift to maintain the same flight path.

Because the wing's maximum lift coefficient is limited, the heavier airplane reaches the critical angle at a higher airspeed. Reducing weight lowers the stall speed, although it does not remove the possibility of a stall.

The aircraft must also remain within its approved loading and centre-of-gravity limits. Weight and Balance Explained covers those relationships in more detail.

Load factor#

Load factor is the ratio between the aerodynamic load carried by the wings and the aircraft's weight. It is commonly expressed in G.

As load factor rises, stall speed rises approximately with the square root of the load factor.

For example, in a coordinated level turn at 60 degrees of bank:

• The load factor is approximately 2 G
• The theoretical stall speed is about 1.41 times the one-G stall speed
• An airplane that stalls at 50 knots in one-G flight could stall at roughly 71 knots under that load

This is why an airplane can experience an accelerated stall during a steep turn, abrupt pull-up, or other high-load manoeuvre despite having substantial airspeed.

Flaps and configuration#

Extending flaps changes the wing's camber and often its effective area. This generally increases the maximum lift coefficient and lowers the stall speed.

Flaps also increase drag, and their effect varies by aircraft and setting. They do not make a stall impossible, and abrupt flap movement can change the aircraft's angle of attack, trim, and load factor.

Extending or retracting landing gear also changes drag and may alter the aircraft's handling, although gear extension does not normally provide the same lift benefit as flaps.

Centre of gravity#

Centre-of-gravity position affects stability, tail loads, elevator authority, control forces, stall behaviour, and recovery characteristics.

A forward centre of gravity commonly requires greater tail force and may result in a higher indicated stall speed. An excessively aft centre of gravity can reduce longitudinal stability and make stall or spin recovery more difficult or, in extreme cases, impossible.

Wing contamination#

Ice, frost, snow, or surface damage can change the wing's shape and disturb its boundary layer.

Contamination may:

• Reduce maximum lift
• Increase drag
• Lower the critical angle of attack
• Increase stall speed
• Reduce or change normal stall-warning cues
• Cause one wing to stall before the other

Even a small amount of contamination can have a disproportionate effect. Aircraft Icing Explained examines this hazard more closely.

Altitude and temperature#

Altitude and temperature do not normally produce a large direct change in the indicated one-G stall speed of a clean subsonic aircraft in the same weight and configuration.

However, they still matter greatly.

At higher density altitude:

• True airspeed at the stall is higher for approximately the same indicated airspeed
• Groundspeed during takeoff and landing is higher
• Engine, propeller, and climb performance may be reduced
• More runway and distance may be needed
• High-altitude aircraft may have a smaller margin between low-speed buffet and high-speed compressibility effects

The indicated stall speed may look familiar while the aircraft travels through the air and over the ground faster. See Density Altitude Explained for the wider performance implications.

Common Situations That Lead to Stalls#

A stall can occur in any phase of flight, but several situations appear repeatedly in training and accident prevention.

Departure stall#

A departure stall may develop after takeoff if the airplane is pitched too steeply, allowed to lose airspeed, or subjected to an excessive angle of attack while climbing.

Contributing factors can include:

• Attempting to clear an obstacle by pulling harder
• Mismanaging pitch after an engine-power change
• Excessive nose-up trim
• Distraction during the initial climb
• A climbing turn with increasing load factor
• Reduced engine performance at high density altitude

The ground is close during departure, so delayed recognition leaves little room for recovery.

Approach-to-landing stall#

During approach, the aircraft is usually slower, configured with flaps or gear, and operating close to the ground.

A stall can develop if the pilot:

• Allows the airspeed to decay
• Tries to stretch the glide by raising the nose
• Uses excessive bank while trying to correct the flight path
• Pulls abruptly during the base-to-final turn
• Fails to manage wind changes or turbulence
• Continues an unstable approach instead of going around

Raising the nose cannot extend a powerless glide indefinitely. It trades airspeed for a temporary change in flight path and can bring the wing to its critical angle.

Skidding base-to-final turn#

A pilot who overshoots the final approach path may try to tighten the turn using excessive rudder while holding opposite aileron.

This cross-controlled, skidding condition combines yaw, bank, and increasing angle of attack. If the airplane stalls, it may enter a spin rapidly and at an altitude too low for recovery.

The safer response to an overshoot is normally a go-around, not an increasingly aggressive attempt to force the airplane back onto final.

Accelerated stall#

An accelerated stall occurs at a load factor greater than one G.

It can result from:

• A steep level turn
• An abrupt pull-up
• Turbulence
• Aggressive manoeuvring
• Pulling out of a dive too sharply

Because the load factor is higher, the stall occurs at a higher airspeed than the published one-G value.

Go-around or trim stall#

Applying substantial power during a go-around can produce strong pitching and yawing effects, particularly if the airplane was heavily trimmed for approach.

If the pilot does not manage the resulting control forces, the nose may rise excessively and the airplane may approach a stall despite the high power setting.

Power does not guarantee protection from a stall.

How Pilots Recognise an Approaching Stall#

Stall cues differ between aircraft, configurations, and flight conditions. Pilots are trained to use several sources of information rather than relying on one instrument or sensation.

Stall-warning systems#

Depending on the aircraft, warning systems may include:

• A horn or buzzer
• A warning light
• A stick shaker
• A stick pusher
• An angle-of-attack display
• Spoken or electronic alerts

A warning usually indicates that the aircraft is approaching the critical angle. It does not grant a fixed number of seconds before the stall, and pilots should not treat the warning as a target to be reached during normal operation.

Some aircraft have no dedicated electronic or mechanical warning device and rely on natural aerodynamic warning characteristics.

Buffet#

Separated airflow may strike the tail or other parts of the airframe and create aerodynamic buffet.

Buffet can be an important warning, but it varies considerably. It may be strong, subtle, masked by turbulence, or altered by configuration and contamination.

Reduced control effectiveness#

As airspeed decreases, the aerodynamic forces available to the control surfaces generally decrease too.

The pilot may notice:

• Lighter control pressure
• Slower aircraft response
• A need for larger control movements
• Difficulty maintaining bank or direction
• Aileron or elevator response that feels less precise

“Mushy controls” are therefore a useful training cue, but they are not a universal or precisely measurable stall indicator.

Uncommanded motion#

A full stall may be accompanied by:

• A nose drop
• A wing drop
• An increase in sink rate
• Rolling or yawing motion
• Inability to arrest a pitch change normally
• Stick-pusher activation in equipped aircraft

Not every airplane responds with the same dramatic nose-down break. Some aircraft display relatively mild pitch changes while continuing to descend at a high rate.

Angle-of-attack indicators#

An angle-of-attack indicator can show the pilot's approximate margin from the critical angle.

These systems can improve situational awareness, but they must be correctly installed, calibrated, interpreted, and used according to their limitations. Some systems account for flap position and other variables differently.

An AOA display supplements sound energy management and aircraft knowledge. It does not replace them.

How to Prevent a Stall#

Stall prevention begins before the warning activates.

Pilots reduce risk by:

• Using the speeds and procedures published in the AFM or POH
• Maintaining coordinated flight
• Monitoring angle-of-attack cues and airspeed trends
• Accounting for weight, bank angle, configuration, and contamination
• Avoiding abrupt control inputs
• Managing pitch and power during climbs and go-arounds
• Going around from an unstable approach
• Avoiding attempts to stretch a glide
• Recognising when load factor is increasing
• Keeping the aircraft within approved weight and balance limits
• Practising recognition and recovery with a qualified instructor

Airspeed is important, but simply staring at the airspeed indicator is not enough. The pilot must understand what the airplane is doing and how close the wing may be to its critical angle.

The Fundamental Stall-Recovery Principle#

The essential action in any aerodynamic stall is:

Reduce the angle of attack below the critical angle.

Until that happens, the wing remains stalled. Adding power, attempting to hold altitude, or levelling a dropped wing cannot substitute for reducing angle of attack.

The exact control movement required depends on the aircraft and the severity of the stall. It may require only releasing back pressure, or it may require a positive nose-down input.

A generic recovery framework#

The FAA's generic framework for conventional airplanes can be summarised as follows:

1. Disconnect automation if applicable. Disconnect the autopilot and autothrottle when required so that they do not resist or obscure the necessary control inputs.
2. Reduce angle of attack. Apply enough nose-down control input to eliminate the stall warning and restore unstalled airflow.
3. Level the wings. Use coordinated controls after reducing angle of attack. Avoid aggressive roll inputs while the wing remains deeply stalled.
4. Apply thrust or power as needed. Use an appropriate amount of power while accounting for torque, yaw, asymmetric thrust, pitch effects, and aircraft limitations.
5. Retract speed brakes or spoilers if applicable. Follow the aircraft-specific sequence.
6. Return to the desired flight path. Recover smoothly while avoiding excessive airspeed, structural loading, altitude loss, or a secondary stall.

This is a generic framework, not a substitute for the aircraft's current manufacturer procedure.

The AFM, POH, operating manual, checklist, or approved training procedure for the particular aircraft takes precedence.

Why “full power immediately” is not universal#

Power can help rebuild energy and reduce altitude loss, but maximum power is not automatically appropriate in every aircraft or every stall.

Potential complications include:

• Strong pitch-up tendencies
• Propeller torque and P-factor
• Asymmetric thrust in multiengine aircraft
• Engine limitations
• Aircraft configuration
• Loss of directional control
• High-altitude engine response
• Manufacturer-specific recovery logic

The correct principle is power as needed, applied in accordance with the aircraft's approved procedure.

Avoiding a secondary stall#

After the wing begins flying again, pulling up too abruptly can raise the angle of attack past the critical value a second time.

The pilot must recover to the desired flight path smoothly, remain within structural limits, and accept that some altitude loss may be unavoidable.

Trying to prevent every foot of altitude loss can delay the initial angle-of-attack reduction or provoke a secondary stall.

Stall Versus Spin#

A stall and a spin are related, but they are not the same condition.

A stall occurs when a wing or part of a wing exceeds its critical angle of attack.

A spin is an aggravated stalled condition involving autorotation. At least part of one wing is stalled, and yaw causes the wings to experience different angles of attack, lift, and drag.

Every aerodynamic spin involves a stall, but most stalls do not develop into spins.

Spin entry becomes more likely when a stall is combined with:

• Uncorrected yaw
• A slipping or skidding turn
• Poor rudder coordination
• Asymmetric thrust
• Aggressive aileron use
• An aft centre of gravity
• Aircraft loading outside approved limits

Spin characteristics and recovery procedures vary greatly. Pilots must use the procedure published for the aircraft. Intentional spins must never be attempted unless the aircraft is approved, correctly loaded, and operated under the applicable rules and training requirements.

Common Myths About Aircraft Stalls#

Myth: A stall means the engine stopped#

An engine failure and an aerodynamic stall are separate events.

An aircraft with failed engines can glide normally. An aircraft with full engine power can stall if its wing exceeds the critical angle of attack.

Myth: Stalls only happen at low airspeed#

Low airspeed is a common path toward a stall, but a high-load manoeuvre can stall the wing at a much higher speed.

The critical angle, not one indicated speed, defines the stall.

Myth: The nose must be high#

An airplane can stall with a level or nose-low pitch attitude.

Pitch attitude and angle of attack are different measurements.

Myth: Adding power fixes the stall#

Power may help the recovery, but it does not by itself reduce the wing's angle of attack.

The pilot must reduce angle of attack first or as the primary action.

Myth: The stall speed in the handbook always applies#

Published stall speeds apply to specified test conditions.

Weight, load factor, configuration, centre of gravity, contamination, and manoeuvring can change the speed at which the critical angle is reached.

Myth: A stall always causes a dramatic nose drop#

Some airplanes have a clear nose-down break. Others buffet, roll, lose control effectiveness, or develop a high sink rate with only a modest pitch change.

The aircraft's design, loading, and flight condition determine its response.

Frequently Asked Questions#

Key Takeaways#

• An aerodynamic stall is caused by exceeding the wing's critical angle of attack.
• A stall can occur at any airspeed, pitch attitude, or power setting.
• Low airspeed is a common condition leading to a stall, but it is not the fundamental cause.
• Published stall speeds apply only to defined weights, configurations, and flight conditions.
• Higher weight and load factor increase stall speed.
• Wing contamination can reduce maximum lift, lower the critical angle, and change warning characteristics.
• Angle of attack is not the same as the airplane's pitch attitude.
• The first and essential recovery action is to reduce angle of attack.
• Power should be applied as needed under the aircraft-specific procedure, not assumed to be universally full power.
• Wings should be levelled with coordinated controls after the angle of attack begins to decrease.
• Some altitude loss during recovery may be unavoidable.
• A spin is an aggravated stalled condition involving yaw and autorotation.
• The aircraft's current AFM, POH, checklist, or manufacturer procedure always takes precedence over generic guidance.

Sources & References#

• FAA Airplane Flying Handbook (FAA-H-8083-3C), Chapter 5: Maintaining Aircraft Control. Covers stall recognition, aircraft-specific stall characteristics, prevention, generic recovery principles, and spins.
• FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25B). Covers angle of attack, lift, load factor, accelerated stalls, stability, weight, and centre-of-gravity effects.
• FAA Advisory Circular 61-67C, Change 2: Stall and Spin Awareness Training. Provides definitions, training guidance, operational factors affecting stall speed, and spin-awareness material.
• FAA Advisory Circular 120-109A: Stall Prevention and Recovery Training. Provides stall-prevention and recovery guidance developed for transport-airplane training.