When did the FAA change the slow flight standard?

The FAA replaced the PTS with the Airman Certification Standards in 2016, and revised the slow flight airspeed target in 2017 to be above the stall warning rather than at minimum controllable airspeed.

Will I fail my checkride if the stall horn goes off during slow flight?

A brief chirp from a momentary bobble is usually acceptable, but a continuous stall warning means you are below the ACS standard and the examiner will likely bust the task.

What airspeed should I target for slow flight in a typical trainer?

Approximately 5 to 10 knots above the published 1G stall speed in the landing configuration. For most Cessna 172s, that's somewhere in the neighborhood of 50–55 knots, but verify with your POH and CFI.

Why is right rudder so important in slow flight?

High power combined with low airspeed and high angle of attack maximizes P-factor, torque, and spiraling slipstream. Without right rudder, the airplane flies uncoordinated, which at high angle of attack is a classic spin entry setup.

Do I use pitch or power to correct altitude in slow flight?

Power. On the back side of the power curve, pulling back to climb only slows the airplane further and increases sink. Hold pitch attitude for airspeed and use throttle to control altitude.

Slow Flight Under the Current ACS - Why Your Old MCA Technique Will Bust Your Checkride

Under the current FAA Airman Certification Standards (ACS), slow flight is flown at an airspeed approximately 5 to 10 knots above the 1G stall speed—not at minimum controllable airspeed (MCA) with the stall horn blaring. If the stall warning is sounding continuously, you are below the standard and will fail this task on a checkride. This change took effect in 2017, and pilots trained under the older PTS method are routinely busting rides because of it.

What Changed Between the PTS and the ACS?

For decades, the Practical Test Standards (PTS) defined slow flight as flight at minimum controllable airspeed—an airspeed where any further increase in angle of attack, increase in load factor, or reduction in power would cause an immediate stall. Pilots were taught to fly with the stall horn screaming continuously, wallowing through the sky with mushy controls while holding altitude within 100 feet.

In 2016, the FAA replaced the PTS with the Airman Certification Standards. A 2017 revision changed the slow flight airspeed target. The stall horn should no longer be on during the maneuver. If it’s blaring, you are too slow.

Why Did the FAA Change the Slow Flight Standard?

The FAA reviewed accident data and found pilots were stalling airplanes in the traffic pattern—base-to-final turns, departure stalls, cross-controlled at low altitude. One contributing factor: pilots were being trained to ignore the stall warning because slow flight practice required flying with the horn on continuously.

The FAA wants pilots to treat the stall warning as exactly that—a warning. The correct response is to reduce angle of attack immediately, every single time. That reflex is what saves lives when an airplane gets slow turning base to final.

What Are the ACS Tolerances for Slow Flight?

The current ACS requires you to maintain:

Altitude: ±100 feet
Heading: ±10 degrees
Airspeed: +5 / −0 knots

That airspeed tolerance is critical. If your target is 60 knots, you can be at 60 or 65, but never 59. Going below the target puts you in the stall warning regime, which is outside the standard.

How Do I Set Up Slow Flight Correctly?

Clear the area first. The ACS requires clearing turns—two 90-degree turns or one 180. The examiner wants to see your head on a swivel and your eyes outside. Half-hearted clearing turns while staring at the attitude indicator cost points before you even decelerate.

Decelerate deliberately. Carb heat on if equipped. Reduce power to approximately 1,500 RPM (varies by airframe). Add back pressure to hold altitude as the airplane slows. Add flaps incrementally as airspeed permits. The ACS requires slow flight in the landing configuration—full flaps, gear down if retractable.

Trim constantly. Every flap setting changes pitch. If you’re not retrimming as you go, you’ll be arm-wrestling the airplane by the time you stabilize. The airplane should fly itself; you should be making small corrections.

Why Does Pitch Control Airspeed in Slow Flight?

On the back side of the power curve, the relationship between pitch and power inverts from cruise flight. Pitch controls airspeed. Power controls altitude.

If you pitch up to gain altitude in slow flight, you slow down further, induced drag increases, and you sink. The correct response:

Low on altitude? Add power. Hold pitch.
Descending? Add power. Hold pitch.
Want to descend? Reduce power.

Pitch has one job: hold airspeed. Throttle has the other: hold altitude. Internalize this or you’ll chase the airplane across the sky.

What Are the Most Common Slow Flight Mistakes?

1. The altitude correction death spiral. You pull back to climb, get slow, stall horn chirps, push forward, descend through target, pull back again. The fix: never pitch for altitude in slow flight. Add an inch of throttle and hold attitude.

2. Forgetting right rudder. High power, low airspeed, high angle of attack—this is peak left-turning tendency. P-factor, torque, and spiraling slipstream are all working against you. Without noticeable right rudder, the ball will sit far right and you’ll be yawing left. Uncoordinated flight at high angle of attack is a spin recipe, and the examiner is watching the ball.

3. Death-gripping the yoke. Stress tightens your grip, which makes control inputs larger, which causes overcontrolling in a mushy airplane. Two fingers and a thumb. The airplane is trimmed—let it fly.

4. Fixating on instruments. The nose-high sight picture in slow flight is distinctive. Learn where the horizon sits on the cowling. Scan outside, inside, outside. At reduced maneuverability, you also need to clear for traffic continuously.

5. Sloppy recoveries. You can fly perfect slow flight and still bust the maneuver on a bad recovery.

How Do I Recover from Slow Flight Without Busting Altitude?

A common failure mode: the examiner calls for recovery, the student shoves in full throttle, and all that nose-up trim pitches the airplane violently upward.

The correct technique:

Power in smoothly—not abruptly
Right rudder—left-turning tendencies are now even stronger
Hold pitch attitude to maintain altitude initially
Retract flaps incrementally as airspeed builds
Carb heat off when appropriate
Trim continuously as configuration changes

Leave slow flight as deliberately as you entered it. A 200-foot balloon on recovery busts the task regardless of how clean the stabilized portion was.

How Should I Practice Slow Flight Before My Checkride?

On your next flight, set up slow flight once—deliberately. Observe:

Where the horizon sits on the cowling
The engine note at reduced power
How much right rudder pressure is required
The trim position
The feel of the mushy controls

Then practice the transitions in and out. Don’t grade yourself—just observe and build familiarity. Repeat every flight until the maneuver feels boring and predictable. That’s the goal. By checkride day, slow flight should be the least interesting thing you do.

Read the Private Pilot ACS and the Airplane Flying Handbook yourself. Both are free FAA downloads. Don’t rely solely on what your CFI tells you—standards change, and you are responsible for knowing the current standard.

Key Takeaways

Slow flight under the current ACS is flown 5–10 knots above the 1G stall speed, not at MCA—the stall horn should not be blaring
Airspeed tolerance is +5/−0 knots; going below your target violates the standard
Pitch controls airspeed, power controls altitude on the back side of the power curve
Noticeable right rudder is required to counter left-turning tendencies at high power and high angle of attack
Practice the recovery as deliberately as the maneuver itself—sloppy recoveries bust the task