ACS Slow Flight Definition

[atpduck]

Not too sure if I like the implications of the new definition of slow flight according to the Private Pilot ACS. http://www.flyingmag.com/pilot-examiners-debate-acs-definition-slow-flight. Learning, and becoming proficient at slow flight is one of the most important aspects of private pilot training. I believe the new ACS definition will alter the way some instructors teach slow flight in order to ensure that their students are able to pass the check ride. Slow flight without the stall warning horn on in a 172, come on!

 

[gotWXdagain]

The ACS is geared to teaching children of the magenta to fly their cirrus's just good enough not to kill anyone.

 

[awbmof]

I started learning slow flight this way a couple of weeks ago during the course of my CFI training. In the 172, we were essentially flying slow-flight at the aircraft's short field approach speed. Now, what I'd like to know, how do you fly slow flight per the ACS if an aircraft was originally certified and doesn't have a aural or visual stall warning system installed?

 

[Jordan93]

I started learning slow flight this way a couple of weeks ago during the course of my CFI training. In the 172, we were essentially flying slow-flight at the aircraft's short field approach speed. Now, what I'd like to know, how do you fly slow flight per the ACS if an aircraft was originally certified and doesn't have a aural or visual stall warning system installed?

The ACS says slow flight maneuver should be 5-10 knots above the 1G stall speed. It shouldn't matter if the plane doesn't have aural or visual stall warning system because you're not demonstrating the maneuver on that criteria

 

[awbmof]

The ACS says slow flight maneuver should be 5-10 knots above the 1G stall speed. It shouldn't matter if the plane doesn't have aural or visual stall warning system because you're not demonstrating the maneuver on that criteria

Thank you for clarifying.


Sent from my iPad using Tapatalk[/QUOTE]

 

[Champcar]

Isn't the design criteria for a stall warning system that it activates 5kts prior to a stall? Hence why it's a WARNING system.

 

[mf_eli92]

I was asked about this change during my CFI checkride. The DPE wanted me to do the maneuver without the stall horn blaring. However once we were back on ground and received my certification, we sat down and discussed about the maneuver and I argued that you'd hear the stall warning 5kts before stall speed which is the speed the ACS wants the maneuver to be performed, at this point we just stared at each other and simply agreed that the stall warning can be calibrated and because of the age of the plane it probably needed some cleaning.

 

[deadstick]

The ACS is geared to teaching children of the magenta to fly their cirrus's just good enough not to kill anyone.

Besides, they have a chute!

Seriously though, when i was instructing I stressed slow flight proficiency and technique. I figured of the student could develop a good control touch at these low speeds, then...
1) they'd have a better feel for the airplane at higher speeds, would minimize over-controlling, and be more accustomed to staying coordinated.
2) they'd have a lower chance of getting into a stall by being proficient at low speed maneuvering.

 

[Grabo172]

I've often use slow flight (the PTS way) to get a student used to how the airplane feels and reacts while in ground effect just prior to touch down and have related it to the students that way. I stress that we're using slow flight to enhance aircraft control and understanding of the aerodynamics of what is taking place with the wing and control surfaces as we slow down down and they become "less efficient".

Can I accomplish this at 50-55 kts instead of 45 kts? Yes. The airplane will still behave like it would in ground effect. Maybe now I think about it more, it's more closely near the usual near touch down ground effect speed.

Will raising the ACS slow flight speed to above the stall warning speed affect how I teach and relate the maneuver to the student? Maybe... But its just shifting where we do the stall warning and buffet training. I'll still take the student down to the stall warning and buffet area like in the PTS, but we will do that as part of the power on and off stall training instead of the slow flight training.

 

[Fly_Unity]

The ACS says slow flight maneuver should be 5-10 knots above the 1G stall speed. It shouldn't matter if the plane doesn't have aural or visual stall warning system because you're not demonstrating the maneuver on that criteria

I believe the stall warning horn is the criteria (or one of them) for slow flight.
From the ACS:

"The applicant demonstrates the ability to: 2. Establish and maintain an airspeed, approximately 5-10 knots above the 1G stall speed, at which the airplane is capable of maintaining controlled flight without activating a stall warning."

This is the response from Christopher Morris at the FAA. You can also read the FAQ on the FAA website.

If the pilot recognizes the stall warning and promptly makes an appropriate correction or airspeed adjustment, a momentary activation of the stall warning horn does not constitute unsatisfactory performance on the maneuver. As with other standards, the problem would arise from continual deviation from the standard, lack of correction, and/or lack of acknowledgment. The goal is to ensure that the applicant does not perform the maneuver with the stall warning activated.

The certification standard in 23.207 states for airplane certification testing, the stall warning must “begin at a speed exceeding the stalling speed by a margin of not less than 5 knots and must continue until the stall occurs.” This is the primary reason the suggested range above stall speed has moved from “3-5 knots” to “5-10 knots without stall warning activation.” The certification standard for the stall warning does play a role in the airspeed selection for the maneuver, and stall warning activation will vary from one airplane to the next, so it is important for the applicant to select an airspeed where the stall warning should not activate except on a momentary basis (e.g., due to turbulence).

The PTS standard for maneuvering during slow flight was for the applicant to 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 an immediate stall.”

The current version of the Airplane Flying Handbook says slow flight should be performed at “the slowest airspeed at which the airplane is capable of maintaining controlled flight without indications of a stall—usually 3 to 5 knots above stalling speed.” The guidance has always intended for there not to be a stall warning, and that is consistent with slow flight guidance published in AC 120-111. However, the 3-5 knot range given does not pair well with the part 23 requirement for a stall warning (§23.207). It is not practical to maneuver in that airspeed range and not have the stall warning, which is an indication of a stall. The standard in the PTS also implies being right above the critical AOA, which means the stall warning would be activated. This result does not align with the guidance, or with what the FAA advocates. Specifically, the FAA does not advocate intentional disregard for a stall warning while maneuvering.

The purpose of teaching slow flight is to ensure that the pilot understands how the airplane responds with less airflow over the flight control surfaces. Since airplanes are operated at low airspeeds and high angles of attack during the takeoff/departure and approach/landing phases of flight, it is essential for pilots to learn the airplane cues and how to operate the airplane in this state. Regardless of airplane type, a pilot does not need to be just below the critical AOA to experience the desired characteristics and achieve the slow flight objectives. These objectives can be accomplished without deliberately activing the stall warning through flight just below the critical AOA. We want to influence the behavior and practices the pilot will follow outside the training environment. Therefore, with the exception of performing a full stall maneuver, a pilot should always perform the stall recovery procedure when the stall warning is activated.

With respect to guidance, the change to AC 61-67 published just prior to the final decision on the AFH wording change, which drove the FAA’s decision to modify this ACS Task element. We are working on another change to ensure the AC will align with the AFH and the ACS and be consistent with AC 120-111. To further explain these changes, we intend to publish a SAFO that is now in formal coordination.

Teaching what an airplane will do at the critical AOA is part of stall training and should be addressed in that context. You allow someone to ‘ignore’ the warning in one narrow instance – as part of stall training. The pilot can still learn what happens at that point – but as part of stall training and learning the proper recoveries – not as part of slow flight.

 

[TonySolis13]

This was probably the most frustrating thing of my PPL checkride on July 1st. I had trained completely under PTS standards, and was taught slow flight in the DA40 at 55kts. At this speed, you are only 6kts away from a stall, so of course the horn is on, but my instructor wanted to emphasize that I could still control the plane, albeit sluggishly. Since my checkride was rescheduled, the new date fell after the June 15th change. Here is where the fun started....

Checkride day, and I breeze through the oral portion. We start to brief the flight and my DPE mentioned the difference in the ACS with the slow flight maneuver. Basically, "I don't want to hear the horn. At all." At that point I remembered that the particular DA40 I had for my exam had a super sensitive stall horn that would start going off at around 66kts-69kts, it wasn't a constant horn, but it was still "hearing the horn". We get up in the air, everything is going great, and the DPE asked for slow flight. I set up for it, and realized that the only speed that I wasn't going to get the horn was by sticking around 72kts, which was pretty much the approach speed of the DA40. Thats a full 17kts faster than I was taught to do it.

I know for a FACT my CFI taught me to be a better pilot learning slow flight at 55kts with the horn blaring. I learned to FEEL what it was like to be on the edge, and know that I was still in control, and not be afraid of that IAS. Now with the ACS, there is no reason to teach that slow, and students will be kept pretty much to approach speeds (at least on the airplane I flew). I get it that the fear is desensitizing the stall horn by "ignoring" it during the maneuver, but I feel that for me it just kept reminding me that I was right on the edge and to focus even more on what I was doing.

Once we landed (I passed), we debriefed and talked about the slow flight in specific. I voiced my concern with it, the DPE told me the advantages of the new ACS standard, and we went our separate ways. Being that I am on track to be a CFI myself, I think this specific thing is going to bug me a little when teaching.

 

[Roger Roger]

I'm sure at least part of this is typical human resistance to change, but the more I hear the more I think that the FAA took a perfectly functional and easy to use document (the PTS) and replaced it with something that sucks. You darn kids get off my lawn, I have to go to Bingo night with @Boris Badenov, where'd I put my dentures, etc etc.

 

[Fly_Unity]

This was probably the most frustrating thing of my PPL checkride on July 1st. I had trained completely under PTS standards, and was taught slow flight in the DA40 at 55kts. At this speed, you are only 6kts away from a stall, so of course the horn is on, but my instructor wanted to emphasize that I could still control the plane, albeit sluggishly. Since my checkride was rescheduled, the new date fell after the June 15th change. Here is where the fun started....

Checkride day, and I breeze through the oral portion. We start to brief the flight and my DPE mentioned the difference in the ACS with the slow flight maneuver. Basically, "I don't want to hear the horn. At all." At that point I remembered that the particular DA40 I had for my exam had a super sensitive stall horn that would start going off at around 66kts-69kts, it wasn't a constant horn, but it was still "hearing the horn". We get up in the air, everything is going great, and the DPE asked for slow flight. I set up for it, and realized that the only speed that I wasn't going to get the horn was by sticking around 72kts, which was pretty much the approach speed of the DA40. Thats a full 17kts faster than I was taught to do it.

I know for a FACT my CFI taught me to be a better pilot learning slow flight at 55kts with the horn blaring. I learned to FEEL what it was like to be on the edge, and know that I was still in control, and not be afraid of that IAS. Now with the ACS, there is no reason to teach that slow, and students will be kept pretty much to approach speeds (at least on the airplane I flew). I get it that the fear is desensitizing the stall horn by "ignoring" it during the maneuver, but I feel that for me it just kept reminding me that I was right on the edge and to focus even more on what I was doing.

Once we landed (I passed), we debriefed and talked about the slow flight in specific. I voiced my concern with it, the DPE told me the advantages of the new ACS standard, and we went our separate ways. Being that I am on track to be a CFI myself, I think this specific thing is going to bug me a little when teaching.

Teach both ways with your students. In fact, teach the fluttering leaf with your students at the same time. Power off, One notch of flaps, yoke all the way back into your lap, do not recover from the stall, stay straight with the rudder, and flutter down a 1000 feet or so.

Im amazed how many pilots are uncomfortable with this maneuver.

 

[MidlifeFlyer]

The change in slow flight is probably the most discussed change. Probably because it is one of the very few substantive changes in the standards. The rest is mostly adding matrix numbers to things that were always there in one form or another. I spoke at a day-long WINGS program two weeks ago in which one of the other seminars was a discussion of ACS by a FSDO rep and attended by a bunch of our local DPEs. They were pretty uniform that there was not very much change in their Practical Test Plans of Action.

Me, I'm pretty neutral on the subject. My theory is that the ACS developers decided to move slow flight from a regimen in which the pilot gets a continuous audible warning to announce relationship to the stall to one in which the pilot needs to maintain control in a configuration which is close but without warnings other than touch, feel and periodic glances at an ASI.

Make sense? Dunno. I think they both have their place in training. Which version of slow flight is actually tested for pilot certification (especially since the ACS reaffirms the stalls must be done to full stall) doesn't strike me as the end of aviation as we know it.

 

[shdw]

I only fly brand new airplanes with the stall horn calibrated to +5 kts Vs/Vso with a deviation of -0/+0.0001 so I teach my students to fly exactly 6 knots above stall speed so they can pass the ride.

Ha who am I kidding, half our planes fire the horn more than 10 knots above stall speed anyway. Making it impossible to pass the new acs ride (love the governments renaming process by the way) in most of the aircraft my applicants will fly in.

I don't much give a rats .... what the government decides to do with verbiage. Teach them to fly, more importantly, cover their instruments and make them feel it. When the day of the ride comes they will be more than equipped to show their examiner whatever he/she wants to see.

All these PTS/ACS standards do is breed more Air France champs. Stop looking at the swirling gauges and look at that massive instrument staring us all in the face. Seems to me that with each new FAA standard release we continue to further lose site of what it means to FLY a plane and get deeper and deeper into the realm of 'head down' Aviation.

 

[Flyinthrew]

The aforementioned SAFO is out.

http://www.faa.gov/other_visit/avia...afety/safo/all_safos/media/2016/SAFO16010.pdf

It would appear to me that the FAA "clarified" it by doubling down on their No Stall Warning methodology. I checked out in a local 172 the other day and when it was time for slow flight we just flew around at 60 knots with the flaps down. Big difference from flying a 1v0 flat scissors like in the past.

 

[killbilly]

Those of who are CFIs...

Will you still teach your students to fly against the stall horn?

 

[Midwest pilot]

Back when I went for my private ride, slow flight often concluded with a power off stall. Ok you're already set up, go ahead and demonstrate a power off stall. Oh yeah and the checkride was $100. But that was way back when you could rent a wet airplane for $33 an hour in 2003.

 

[Flyinthrew]

Those of who are CFIs...

Will you still teach your students to fly against the stall horn?

Probably only if it can be positively transferred to some other learning objective. To spend time on it simply because I think it is important is a distraction, and can be construed as a waste of my student's money. Yeah, I believe exploring the entire envelope is incredibly important and I'll invite students to do so with me or another CFI after their checkride. I also think spinning your airplane is important if it is allowed, but I don't teach that either.

 

[killbilly]

Probably only if it can be positively transferred to some other learning objective. To spend time on it simply because I think it is important is a distraction, and can be construed as a waste of my student's money. Yeah, I believe exploring the entire envelope is incredibly important and I'll invite students to do so with me or another CFI after their checkride. I also think spinning your airplane is important if it is allowed, but I don't teach that either.

The reason I ask the question is that I remember being intimidated by hearing the stall horn when I was first learning to fly. It took a good chunk of flying at MCA to get over the idea that it was something manageable and "normal" and nothing to get nervous about.