The FAA's New "Not-So-Slow" Slow Flight Procedure

As most flight instructors know the FAA recently changed the requirements for slow flight in the private pilot ACS. Slow flight must now be accomplished at a speed higher than MCA or Minimum Controllable Airspeed (a speed at which the stall horn is continuously activated). Why? The FAA feels that when pilots hear a stall horn, they should take immediate stall-recovery action. If slow flight is practiced at MCA, then the stall horn will be heard continuously without the pilot going through the motions of recovering from a stall. The FAA feels that this will desensitize pilots to the stall warning, thus making them less likely to recover from an actual stall should one occur in flight. The FAA, however (and with all due respect), is a little confused about the purpose of a stall warning horn.

The activation of a stall warning horn or light is not an indication of a stall. It’s an indication that the airplane’s wings are approaching their critical angle of attack—the angle of attack that, when reached, results in a stall. In fact, the airplane’s speed at the moment the stall warning activates is at least 5 knots above stall speed, if not more.

FAR Part 23 requires a stall horn/light to activate at a minimum of 5 knots above the airplane’s actual stall speed. In many instances, the warning can activate at a slightly higher speed above the airplane’s actual stall speed (it all depends on the manufacturer of the stall warning unit to say nothing about how normal wear affects the device). When the stall warning activates, the airplane is still flying. Yes, it’s flying on the back side of the power curve, but it’s still flying. You can still turn right, left, descend and even climb in most small airplanes. The controls are mushy, but they still work. Stall warning activation doesn’t imply that your airplane has stalled. Nevertheless, the FAA conflates and confuses the stall warning with an actual stall.

Now, don’t get me wrong here. If a pilot heard the stall horn and wasn’t expecting to hear it, then he’s clearly closer to the critical angle of attack than he thinks he is. In this instance, he should apply standard stall recovery procedures: reduce angle of attack and add power. This is why the stall horn/light is called a stall warning device and not a stall detection device. It warns a pilot of an impending stall should he or she continue to increase the angle of attack (a stall detection device would activate only when the critical angle of attack is reached, and what good would that be to a pilot?).

What if the pilot intends to fly at the airplane’s minimum controllable airspeed? In this instance, the pilot would expect to hear the stall warning. After all, he knows he will be operating very close to the critical angle of attack. Hearing the stall horn when he expects to hear it doesn’t in any way diminish the value of hearing a stall horn when he doesn’t expect to hear it. Expecting something and not expecting it are two distinct psychological states in which a stall warning device serves the pilot. After all, when my kitchen’s smoke alarm goes off when I’m cooking (as I often expect it to) that doesn’t mean I’m less likely to respond appropriately to a smoke alarm when I’m not cooking. Context is very important here. Hearing a stall warning when flying at MCA doesn’t diminish its value in alerting a pilot to an unexpected stall, should one be imminent. (If you want to know the primary reason a pilot might disregard the stall horn/light, then read my License to Learn column in the November 2016 issue of AOPA Pilot titled, When Pilots Stall and Don’t Recover.)

The meaning offered by the stall warning device depends on how a pilot is flying his or her airplane at any given time. To say that a pilot should always apply stall recovery procedures when the stall horn activates is to limit his ability to properly fly his machine. After all, it’s possible that you might hear a stall horn activate in a Cessna 172 (stalls at 50 knots IAS) when descending at minimum sink speed (57 knots IAS). You’ll also hear a stall horn if you want to make a turn (at MCA) in the shortest radius to extricate yourself from a boxed environment. The stall horn will also wail continuously when practicing falling leaf stalls—an essential maneuver for teaching the proper use of rudder in stall recovery. And if you want to learn how an airplane handles during the landing flare—and what student doesn’t?—you’ll need to practice flying slow at MCA.

So how will the FAA’s new slow flight policy affect the development of private pilots? Unfortunately, newly certified private pilots will have little or no experience operating the airplane on the back side of its power curve. Oh wait, you say. Flight instructors can still teach flight at MCA. Maybe so, but wouldn’t that directly contradict the FAA’s original rationale for increasing the speed at which slow flight is performed? Do you actually think that FAA inspectors giving CFI candidates their checkrides are going to look favorably on CFI applicants who slow-fly with the stall horn activated? I don’t think so. The fact is that slow flight at MCA will disappear from aviation’s cultural knowledge base in the same way that the knowledge to perform steep spirals disappeared from the aviation community many years ago when the FAA removed steep spirals from the PTS. The FAA put steep spirals back in the PTS 10 years (+/-) later. When they did, very few instructors knew how to perform, much less teach this maneuver.

This, however, isn’t the really big concern I have with the new slow flight change. The first of two serious issues with this new policy involves the speed at which the FAA recommends that students fly slow. In its recent Slow Flight SAFO, the FAA’s method of determining the allowable speed at which to slow fly will permit the maneuver to be performed at speeds up to 1.34 Vs. Yes, you read that correctly: 34% above stall speed. That’s higher than the approach speed recommended for today’s modern trainer (which is 1.3 Vs). The second serious issue with the new slow flight requirement is how it detracts from learning basic attitude flying skills. The new slow flight requirement forces students to focus on their airspeed indicator to prevent activating the stall horn. When slow flight was practiced at MCA, students primarily focused on managing their angle of attack and flying coordinated by looking outside the airplane. There was no reason to look at the airspeed indicator because the student’s ears were free to assess the proximity to the critical angle of attack. With the FAA’s new slow flight requirement, students are now compelled to spend more time with their eyes directed inside the cockpit focused on their airspeed indicator. Basic attitude flying skills will diminish as a result.

Keep in mind that the FAA and NTSB have pushed hard for the past several years to reduce loss of control accidents (LOC). These types of accidents imply that there was a deficiency in a pilot’s ability to control the airplane. These pilots didn’t suffer from a loss of “decision making ability” or loss of “risk managing ability.” They suffered from a loss of “control,” which involves the flight controls of an airplane. Every bit of evidence available today suggests that pilots primarily lose control of their airplanes because they fail to fly them properly, not because they fail to make a decision properly or manage a risk properly (yes, judgment and risk management play a part, no doubt. But the evidence suggests that these are not majority players in aviation accidents (read the HFACS 2005 studies for evidence of this assertion). So, how does a dumbing-down of basic airmanship skills as a result of the new slow flight requirement help reduce LOC accidents? It doesn’t. And that’s the sad part about the direction the FAA has taken with its new flight training philosophy.

Over the past 15 years, beginning with FITS (FAA Industry Training Standards), the FAA has moved toward an airline-type training philosophy for general aviation pilots. The process continues with the ACS’s new slow flight requirement. As the FAA sees it, if airline pilots are trained to apply stall recovery procedures upon activation of an airliner’s stick shaker, why shouldn’t general aviation pilots do the same the moment the stall horn is heard in the cockpit? If airline pilots don’t make power off approaches, why should general aviation pilots make them? (Power off approaches have almost disappeared from our current training milieu.) If airline pilots do line oriented flight training (LOFT), why shouldn’t private pilots do the same? LOFT is the reason the FAA now recommends that ab initio student pilots learn the basics of flying an airplane during short cross country trips, thus avoiding the practice area. No, I’m not making any of this up. It’s all documented (read my other blogs). What the FAA fails to consider is that general aviation pilots are not airline pilots. Big surprise, right? In fact, there’s nothing about flying bigger airplanes that pertain to flying smaller ones; but everything about flying smaller airplanes pertains to flying bigger ones. Ultimately, the FAA is either unwilling or unable to understand this concept. Once again, I am not anti FAA; I'm anti bad ideas. 

By Rod Machado | | PTS-ACS Arguments | 12 comments
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  • David Scott - - June 16, 2017

    Hi Rod !

    Thanks again for writing the well known instructor logic for maneuvers and straight forward distinctions where training evaluation standards are going wayward.

    One thing all CFI pilots need awareness is that some maneuvers are no longer really something good to practice and teach in all small aircraft. There are some for which some maneuvers, even though the old PTS requires them, and maybe perhaps even the new ACS standards, should never be attempted because of the added risk now associated to their design.

    A prime example is the Cirrus aircraft models. They are certificated FAR 23 airplanes. But they do not meet the flight characteristics required for FAR 23 strictly. They were given an exemption to meet the stall and stall recovery requirements. It is well documented that the aircraft will not recover from a stall / spin scenerio in the FAR 23 requirement. Their exemption was allowed with assumption that equivalent safety is provided because of the parachute system. If unsuspectingly you did not know this, a falling leaf stall maneuver from the usual 3000 feet above ground start point will leave the dentist making a visit to the morgue for an evening. They happen to also be susceptible to aileron over control from low stick movement for respective control surface movement, something also which may become a factor during stalls maneuvers with the aircraft, which in turn may place the three wheel vehicle into a spin.

    I really enjoy your wordings to relate and share knowledge with others. The whole stall warning relationship to a smoke detector is a great analogy.

    Keep up the great articles -

    David Scott CFIAI
    Washington, IL

  • Mike Savage - February 06, 2017

    Slow flight is just plain fun — why take that away? The engine growling, lots of rudder, nose pointed up, flaps down, airspeed shows zero, stall horn blaring and still hauling back on the wheel to make it stall! (Cessna 172)

    Aw, c’mon now. We should at least know how to do this safely!

  • Jason Phillips - December 31, 2016

    Recently (Oct. 2016), I passed a CFI Initial with an inspector of the ABE FSDO. I was concerned about performing slow flight because of the discrepancy between the Private ACS and the CFI PTS. The CFI PTS is Minimum controllable airspeed. Before the flight portion I asked the examiner what he expected me to perform. The answer was MCA as per the CFI PTS.

  • Ulrich Hasche - December 18, 2016

    Hello Rod,

    I am a german pilot reading your column since a few years. I purchased some of your books online and saw you from a distance when you spoke to a crowd at Oshkosh 2016. I always enjoyed your topics and the your personal style to deliver serious points to all kinds of people.

    Congrats and thank you for all your work and the open minded words to the FAA in your last column. I will miss it but I understand and respect your decision. (I am retired too – as a teacher)

    You wrote you want to write more books and develop more eLearning courses. I am glad you will still provide your knowledge to others.

    Request: Would it be possible to make a book of all your columns or a series of books or at least a “best of” ? Because I could read your column only maybe 5 years but can imagine to learn something also from older ones. “A good pilot is always learning” and I try to be a good one.

    Stay healthy, safe flying! Merry Christmas and a happy New Year!


  • Jeff Benson - December 02, 2016

    We who read AOPA from cover to cover each month Will sorely miss you but so glad that you are continuing to pass your wisdom on through your other established media.
    I have flown for 40 years, with 38 of those professionally and have amassed 27,000 accident free hours.
    That said I learned something new from your column in AOPA every month.
    Bless you as you shift course ever so slightly.
    Jeff Benson
    AOPA 788851

  • Bob Cherry - November 28, 2016

    Hey Rod, I’m Bob Cherry, 20 years a flight school owner/operator and CFII since 1990 and a great fan of you and your writings for many a year. What you have had to say and how you have chosen to say it have been “required readings” for many a student of yours truly.Your many writings will still be’required readings" for so long as I hang around the skys of the Trenton Mercer Airport, but your articles for AOPA will certainly be missed. They have been eye openers for many a subject which likely would have gone unnoticed not the least of which was your most recent “too slow for slow flight”. Thanks to your from the many who have come to appreciate your incites. Warmest regards.

  • Matt Bowers - November 28, 2016

    This new rule kills all the great techniques I teach for flying the maneuver as well as the knowledge I impart from it.

    During initial primary training, I teach to look outside 90% of the time. This now sounds more like a mostly instrument maneuver.

    I doubt any of my or Rod’s students would smack an airliner into a sea wall!

    Thx for all your books & articles.

  • Mark Fields - November 25, 2016

    Rod, you may be right about the FAA’s rationale for revising slow flight being rather ‘stoopid’, but then again, you may be nearer to the upper end in terms of PMH – pilot mental horsepower. Although the FAA would likely never permit it, a switch to temporarily switch to a visual the stall warning for say 90 seconds might satisfy both them & you. My daughter (17) is in primary flight training & I damn sure want her to experience, understand & learn to manage being behind the power curve. By the way, you have a terrible sense of humor, similar to my own – “If life isn’t funny then lower your standards,” yaKnowWhutImeanBubba?
    Actually, I don’t consider myself more than a mediocre pilot but I may have had an episode of what the FAA wants to avoid. Returning home from a 3.7 hour flight in my ‘new’ to me steam gauge 182T, it was after dark & I was fatigued & sick. I had very little mental headroom to deal with an increased workload & it took me about two seconds to respond to the stall warning horn. Fatigue? 1982 primary flt training? The best lessons are the ones you survive, and no – I wasn’t too broke to pay attention.

  • Robert Harrison - November 22, 2016

    Spot on Rod; As a 75 yr. old active CFI/former Naval Aviator/former airline pilot/former corporate pilot, I am a firm believer in teaching fundamental airmanship with emphasis on the lower end of the flight envelope. One technique I like when a student is into learning to land is to fly with a bit of throttle in the flared attitude in ground effect down most of the length of a long runway. Also have students fly S&L at 1000’ or so with ALL instruments covered.
    Thanks for your good work. Bob, #1652697CFI

  • Grace Schoenemann - November 22, 2016

    As always, spot on Rod.

  • Buz Massengale - November 21, 2016

    If flight training is trending toward a more airline style ab initio profile, then it’s time to increase the minimums required for certification and to increase the certification requirements for aircraft. Perhaps requiring the installation and training on the use of angle of attack indicators for all airplanes would be the next step. Nothing like making it more difficult and expensive to participate in aviation.

  • Bruce Mamont - November 21, 2016

    Stalls aren’t an instrument ACS task, but usually in the training syllabus. Should recovery be initiated at the horn or should instrument students actually enter a full stall? Seems to me the former.

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