Commercial Pilot ACS Study Guide: Accelerated Stalls

Accelerated stalls challenge one of the most common misconceptions about stalls: that they only happen when an airplane gets too slow.

An airplane can exceed its critical angle of attack at any airspeed and in any attitude. When additional load is placed on the wings during a turn, pull-up, or other maneuver, the airplane can stall at an airspeed significantly higher than its normal wings-level stall speed.

For the commercial pilot, accelerated stalls are an important lesson in load factor, energy management, and angle-of-attack awareness—especially during maneuvering flight.

What Is an Accelerated Stall?

An accelerated stall occurs when the airplane stalls while experiencing a load factor greater than approximately 1 G.

In straight-and-level, unaccelerated flight, the wings support roughly the weight of the airplane. During a level turn or abrupt change in flight path, the wings must produce additional lift.

Producing that additional lift requires an increase in angle of attack. As the load factor increases, the airplane moves closer to its critical angle of attack.

The result is simple:

More load on the wing = higher stall speed.

This is why an airplane can stall well above the published 1-G stall speed.

Load Factor Changes Stall Speed

The relationship between load factor and stall speed is one of the most important concepts behind accelerated stalls.

Stall speed increases approximately with the square root of load factor:

Accelerated Stall Speed = Normal Stall Speed × √Load Factor

For example, if an airplane stalls at 50 knots at 1 G, then at 2 G:

50 × √2 ≈ 71 knots

The wing still stalls for the same fundamental reason—it reaches its critical angle of attack. The increased load simply causes the airplane to reach that condition at a higher airspeed.

Bank Angle and Load Factor

In a coordinated level turn, increasing bank angle increases load factor.

Approximate examples include:

• 30° bank: 1.15 G
• 45° bank: 1.41 G
• 60° bank: 2 G

The increase becomes progressively greater as bank angle approaches 90°.

At 60° of bank, the airplane experiences approximately 2 G, and its stall speed is roughly 41% higher than its 1-G stall speed.

This is why steep turns require disciplined pitch and bank control. Increasing back pressure to maintain altitude increases the aerodynamic load on the wings and reduces the available stall margin.

Airspeed Does Not Define the Stall

Accelerated stalls reinforce a concept that commercial applicants should be able to explain clearly:

The wing stalls because it exceeds its critical angle of attack—not because it reaches a specific airspeed.

Published stall speeds are based on defined conditions. Change the load factor, weight, configuration, or other operating conditions, and the airspeed at which the critical angle of attack is reached may change.

A pilot who relies exclusively on the airspeed indicator may therefore miss the aerodynamic conditions developing around the airplane.

How an Accelerated Stall Develops

During training, the maneuver demonstrates how quickly an increase in aerodynamic loading can produce a stall.

The airplane is established in the appropriate configuration and maneuvered according to the ACS and aircraft-specific procedures. As bank and back pressure increase, load factor rises.

The pilot should notice:

• Increasing control pressure
• Increasing G-loading
• Reduced stall margin
• Stall warning or buffet
• Changes in control response
• The importance of coordination

The maneuver should be performed smoothly and deliberately. The objective is not to make the stall abrupt—it is to understand why the stall occurs at a higher-than-normal airspeed.

Coordination Is Critical

Accelerated stalls can become significantly more hazardous when the airplane is uncoordinated.

If yaw is present as the airplane reaches its critical angle of attack, one wing may stall more aggressively than the other. This can produce a rapid wing drop and create conditions favorable for spin development.

Maintain coordinated flight throughout the maneuver and use proper rudder input rather than attempting to correct yaw with inappropriate aileron.

At increased load factors, small control errors can produce much larger consequences.

Where Accelerated Stalls Become Dangerous

The practical value of accelerated stall training becomes clear when considering real-world maneuvering.

Potential scenarios include:

• Steep turns
• Abrupt pull-ups
• Base-to-final corrections
• Overshooting a runway centerline
• Maneuvering close to terrain
• Aggressive avoidance maneuvers
• Excessive back pressure during a turn
• Rapid changes in flight path

A particularly dangerous situation can develop when a pilot overshoots final, increases bank, and applies excessive back pressure in an attempt to return to the runway centerline.

The combination of bank, increased load factor, reduced airspeed, and possible uncoordinated flight can rapidly reduce the remaining stall margin.

If the approach becomes unstable, the safer option is to go around rather than force the airplane back into position.

Maneuvering Speed and Accelerated Stalls

Accelerated stalls also provide an opportunity to understand maneuvering speed (VA).

At or below the appropriate maneuvering speed, an airplane in a simplified certification context is designed so that a full, abrupt control input in one axis should result in an aerodynamic stall before exceeding certain structural load limits.

However, VA is not a universal protection speed.

Pilots should understand that:

• VA changes with aircraft weight
• Lower weight generally means a lower VA
• VA does not protect against every type of control input
• Multiple or rapid control inputs can still create excessive structural loads
• Turbulence can impose loads independent of pilot control inputs

Do not treat maneuvering speed as permission to make aggressive control inputs.

Recovering From an Accelerated Stall

Regardless of the airspeed or attitude in which the stall occurs, the fundamental aerodynamic problem remains the same:

The wing has exceeded its critical angle of attack.

Recovery begins by reducing angle of attack.

The pilot should then:

• Maintain coordinated control
• Apply appropriate power
• Correct excessive bank as appropriate
• Allow the airplane to accelerate
• Return smoothly to the desired flight path
• Avoid creating a secondary stall

Trying to preserve altitude by immediately applying excessive back pressure can keep the wing near its critical angle of attack or produce another stall.

Don’t Confuse G-Loading With Airspeed

One of the most valuable lessons from accelerated stall training is that a healthy-looking airspeed does not necessarily mean there is a large stall margin.

Consider an airplane in a steep turn. The airspeed may appear comfortably above the published stall speed, but the increased load factor has also increased the airplane’s actual stall speed.

The question becomes:

How much aerodynamic margin is actually available at the current load factor?

That is a more useful commercial-pilot perspective than simply comparing indicated airspeed to a published stall number.

Common Errors

Watch for:

• Focusing only on airspeed
• Poor understanding of load factor
• Excessive or abrupt control inputs
• Improper bank control
• Poor rudder coordination
• Failure to recognize stall indications
• Delayed reduction in angle of attack
• Excessive altitude loss during recovery
• Aggressive pullout after recovery
• Secondary stall
• Failure to maintain situational awareness

The maneuver should demonstrate aerodynamic understanding as much as aircraft-handling ability.

What the DPE Is Looking For

Be prepared to demonstrate and explain:

• What causes an accelerated stall
• The relationship between load factor and stall speed
• How bank angle affects load factor
• Why the airplane can stall above its published stall speed
• Critical angle of attack
• Proper coordination
• Stall recognition
• Correct recovery technique
• Secondary stall prevention
• The relationship between accelerated stalls and maneuvering speed
• How accelerated stalls apply to real-world maneuvering

A commercial applicant should be able to connect the numbers to what is physically happening to the airplane.

Checkride Knowledge

Before your checkride, make sure you can answer:

Does an airplane always stall at the published stall speed?
No. A stall occurs when the wing exceeds its critical angle of attack. Load factor and operating conditions can change the airspeed at which that occurs.

What happens to stall speed as load factor increases?
Stall speed increases.

What is the load factor in a coordinated 60° level turn?
Approximately 2 G.

How much does stall speed increase at 2 G?
Approximately 41%.

Why does pulling back in a steep turn increase stall risk?
Increasing back pressure increases angle of attack and aerodynamic loading, reducing the remaining margin before the critical angle of attack.

What is the first priority when recovering from an accelerated stall?
Reduce the angle of attack below critical.

Final Takeaway

Accelerated stalls demonstrate why stall awareness cannot be reduced to watching a number on the airspeed indicator.

As load factor increases, stall speed increases with it. A pilot maneuvering aggressively may therefore reach the critical angle of attack while flying considerably faster than the airplane’s published wings-level stall speed.

Commercial pilots should learn to recognize the complete aerodynamic picture: bank angle, load factor, angle of attack, coordination, and available energy.

Understanding those relationships is what turns accelerated stall training from a checkride maneuver into practical loss-of-control prevention.

Don’t just know your airspeed—understand what you’re asking the wing to do.

FAA References

• Commercial Pilot for Airplane Category Airman Certification Standards, FAA-S-ACS-7B
• Airplane Flying Handbook, FAA-H-8083-3C
• Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25C
• Aeronautical Information Manual (AIM)
• Aircraft-specific POH/AFM