Slow Flight, the Twenty Seventeen ACS Change, and Why the Stall Horn No Longer Blares in the Checkride Maneuver Everybody Gets Wrong

Under the FAA’s 2017 Airman Certification Standards (ACS), maneuvering during slow flight is flown at an airspeed where the stall warning is NOT activated - not on the ragged edge with the horn blaring like the old Practical Test Standards demanded. This single change trips up more private pilot applicants than almost any other maneuver, largely because instructors trained before 2017 often still teach the outdated method. The goal now is to fly slow while keeping the warning quiet, and to respond immediately the moment it chirps.

What Is Slow Flight and Why Does It Matter?

Slow flight - officially “maneuvering during slow flight” in the ACS - is the airplane at the exact configuration and airspeed you’ll see on final approach, on a short field, and during a go-around: slow, heavy, and nose-high.

This is the corner of the flight envelope where real accidents happen. The base-to-final turn. The overshoot. The stall that rolls off a wing thirty feet above the runway.

If you genuinely own slow flight - if you’re comfortable flying the airplane when it’s barely willing to fly - you become a safer pilot every single time you come back to land. This maneuver is not a party trick or examiner cruelty. It’s rehearsal for your last four hundred feet before every landing you’ll ever fly.

What Changed in the 2017 ACS?

For decades, slow flight was taught one way: slow the airplane, add power, raise the nose, and fly it right on the ragged edge at minimum controllable airspeed. Many instructors described the target as flying with the stall warning horn blaring continuously. The horn screaming was the badge of honor - proof you were truly on the edge.

In 2017, when the FAA rolled out the Airman Certification Standards (ACS) to replace the old Practical Test Standards (PTS), they redefined the task. The new target is an airspeed above the point where the stall warning activates.

Here’s the whole ballgame: under the current standard, you fly slow flight at an airspeed where the stall warning - horn, light, or buzzer - is not activated. The old horn-blaring method is now wrong. If the warning goes off during the maneuver, you’re too slow.

Why Did the FAA Change the Slow Flight Standard?

The change was driven by accident data. The FAA and the National Transportation Safety Board (NTSB) saw too many loss-of-control accidents happening at low altitude, low airspeed, and high angle of attack.

The problem was that the old training taught pilots to be comfortable ignoring the stall warning. For decades, students learned that the horn was just background noise during a normal maneuver - then they’d fly a real airplane into the ground with the horn going off, because they’d been trained that the horn was normal.

The philosophy shifted to: respect the warning. When the airplane tells you it’s about to stop flying, that means something. Fly slow, fly right up near the edge, but keep the warning quiet. If it chirps, add a little power or lower the nose slightly to silence it. You’re training the reflex that a real stall warning demands a real response.

Why Do So Many Pilots Still Fly It Wrong?

If your instructor learned to fly before 2017 - and many excellent instructors did - there’s a real chance they were taught the old way, and some still teach it out of habit.

That creates a dangerous mismatch: your CFI may say “fly it with the horn on,” and then you arrive at the checkride where the examiner expects the horn to be off. That disconnect has busted more than a few applicants who did exactly what their instructor told them.

It isn’t your fault when that happens, but it is your problem. Walk in knowing the current standard cold so it never bites you.

What Is the Examiner Actually Looking For?

Here’s what the ACS requires, in plain language:

• Clear the area first. Always. Nobody below you, nobody about to fly through your airspace while you’re crawling along nose-high.
• Establish and maintain an airspeed at which any further increase in angle of attack, increase in load factor, or reduction in power would result in a stall warning. You’re flying just above the warning.
• Accomplish coordinated turns, climbs, and descents in that configuration - not just straight flight. The examiner may ask you to turn left, turn right, or climb while holding the slow, high-power configuration.

The tolerances you must hold:

• Altitude: ±100 feet
• Heading: ±10 degrees
• Airspeed: +10 knots and −0 knots

Read that airspeed tolerance carefully: +10 and −0. You can be a little fast. You cannot be slow - because slow means you tripped the warning and missed the entire point of the maneuver.

How Do I Actually Fly Slow Flight, Step by Step?

1. Start at a safe altitude. Use at least 1,500 feet above the ground, and higher is better, so a stall break leaves you plenty of room to recover. Clear the area with a couple of 90-degree turns - look around and look below.

2. Reduce power. Add carburetor heat if your airplane calls for it. As the airplane slows, raise the nose to hold altitude. The nose will come up and up, and the airplane will feel heavy and reluctant. Nothing is wrong - that’s the airplane hanging on the back side of the power curve.

3. Add power back in as you approach your target speed. Down here, the controls work backwards from cruise: power controls altitude and pitch controls airspeed. If you’re sinking, don’t pull back - add power. If you get too slow and the horn chirps, lower the nose a hair and add a touch of throttle.

4. Set your configuration deliberately. The maneuver may be flown in the landing configuration - gear down, full flaps - or in a configuration the examiner specifies. Many examiners want to see it dirty (full flaps) because that’s the approach configuration where it matters. Know which one you’re being asked for.

5. Build the reflex. The second the stall warning makes a sound, respond - not with a big dramatic push, but a small, smooth reduction in angle of attack plus a little power, flying right back up to your target just above the warning. Fly with small, gentle, constant corrections. This is not a set-it-and-forget-it maneuver; you’re working actively the entire time.

How Does Slow Flight Connect to Stalls and Go-Arounds?

Picture a checkride: you’ve nailed slow flight, horn quiet, altitude locked in. The examiner says, “Now give me a power-off stall from this configuration.” You do it, recover, and think you’re done.

But a sharp examiner is evaluating something bigger across that whole block. Slow flight, approach-to-landing stall, and go-around are not three separate tricks. They’re one continuous story about the slow, dirty, nose-high corner of the envelope - the story of your last four hundred feet before every landing.

The applicant who flies slow flight like they mean it, and responds to that first chirp of the horn like it’s real, isn’t just passing a checkride. That’s the pilot who, three years later, feels the airplane get mushy on a gusty base-to-final and instinctively lowers the nose and adds power before the wing ever quits. The checkride is just the day somebody watches you prove it.

What Are the Most Common Slow Flight Mistakes?

Flying it with the horn on. The old habit, often taught by pre-2017 instructors. Fix it now: keep the warning quiet.

Getting behind the airplane on power. Students slow down and forget how much throttle it takes to hold altitude down there. You’ll need far more power than feels natural - in many trainers you carry substantial power just to hold level flight. Don’t be shy with it.

Lazy feet. At high power, low airspeed, and high angle of attack, you’re in left-turning-tendency city. If your feet fall asleep, the airplane yaws, the ball slides out, and now you’re uncoordinated at low speed - exactly the setup for a wing dropping in a stall. Step on the ball. Your feet should be busy the entire maneuver.

Chasing altitude with pitch. The deepest habit to break. Down here, pitch is airspeed and power is altitude. Fight that and you’ll porpoise all over the sky, trip the horn, and bust the task. Trust the back side of the power curve.

The Real Goal: Familiarity, Not Fear

Slow flight feels scary when you think the goal is to flirt with disaster. It’s the opposite. The goal is to become so familiar with the airplane’s quiet, reluctant, low-speed personality that it stops being scary at all.

Spend enough time up at altitude, with room to spare, feeling exactly what the airplane feels like right before it’s done flying - and when you meet that same feeling near the ground, you’re not surprised and you’re not afraid. You just fly the airplane.

The task details come straight from the FAA’s Airman Certification Standards for the private pilot, and the history behind the 2017 change is documented in the FAA’s own guidance and the safety data that drove it. Read the actual task language for yourself - it’s all right there in the standards.

Key Takeaways

• Fly slow flight with the stall warning silent. Under the 2017 ACS, the target airspeed is just above where the stall warning (horn, light, or buzzer) activates - not the old horn-blaring minimum controllable airspeed.
• The change was driven by loss-of-control accident data. The FAA and NTSB wanted pilots to respect the warning, not ignore it.
• Know the tolerances cold: altitude ±100 feet, heading ±10 degrees, airspeed +10/−0 knots. You can be fast, never slow.
• Down low, controls reverse: power controls altitude, pitch controls airspeed. Keep the airplane coordinated with active rudder.
• Watch for the instructor-vs-examiner mismatch. Pre-2017 CFIs may still teach the horn-on method; the checkride expects it off.