stall recovery

[767]

No, I'm quite certain that he meant your stall recovery technique. How did any of your students get that past the examiner? Unless the examiner was also the Class I who trained you on that technique...The largest concern for all of us here isn't that you've said you'll stop teaching it that way; it's that you taught it that way at all. How many licenced pilots are there out there who are certain that the way to recover from a stall is to add power first? For that matter, who taught you, and how many other instructors were taught the same thing, only to pass it on to their students? On the other hand, this seems like the kind of thing that you came up with yourself after a moment's thought on the use of power to arrest descent, without any in-depth consideration for the actual aerodynamics involved, or a complete lack of understanding thereof.

Hmm.. well, as far as im concerned, the job of the examiner is to see if the candidate meets the standard of the exercise being demonstrated. Ive posted below from the flight tets guide on ex 12.

http://www.tc.gc.ca/civilaviation/gener ... 3/menu.htm
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Aim

To determine that the candidate can recognize indications of the approach to arrival stalls, the full stall and can accomplish a positive and smooth recovery with a minimum loss of altitude.

Description

At an operationally safe altitude that allows recovery at or above 2,000 feet AGL, or the minimum height recommended by the manufacturer, whichever is higher, the stall manoeuvre will be entered from a power off situation. The examiner will specify the aeroplane configuration for the stall demonstration.

Performance Criteria

Assessment will be based on the candidate's ability to:

a.complete appropriate safety precautions before entering a stall;


b.establish the specified configuration;


c.transition smoothly to a pitch attitude that will induce a stall;



d.recognize the onset of the stall by identifying the first aerodynamic buffeting or decay of control effectiveness;


e.stall the aeroplane;


f.maintain directional control;


g.promptly and smoothly recover using control applications in the proper sequence;


h.avoid a secondary stall and excessive airspeed or altitude loss

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So as you can see, they dont specify the exact sequence of recovery. All they say is that the candidate should recover with minimum loss of altitude. Maintain directional control (with rudder of course, and ailerons neutral). Instead of saying proper sequence, they should say nose down first, and so on. It might be that the examiner might have a different opinion of what the "proper" sequence is than the instructor. I would hope TC lists the standard sequence on the FTG, in our case, nose down first.

[FlaplessDork]

So as you can see, they dont specify the exact sequence of recovery. All they say is that the candidate should recover with minimum loss of altitude. Maintain directional control (with rudder of course, and ailerons neutral). Instead of saying proper sequence, they should say nose down first, and so on. It might be that the examiner might have a different opinion of what the "proper" sequence is than the instructor. I would hope TC lists the standard sequence on the FTG, in our case, nose down first.

I can quote Transport too:

Stall Recovery

The key factor in recovery from a stall is regaining positive control of the aircraft by reducing the angle of attack. At the first indication of a stall, the wing angle of attack must be decreased to allow the wings to regain lift. Every aircraft in upright flight may require a different amount of forward pressure to regain lift. It should be noted that too much forward pressure could hinder recovery by imposing a negative load on the wing. The next step in recovering from a stall is to smoothly apply maximum allowable power to increase the airspeed and minimize the loss of altitude. As airspeed increases and the recovery is completed, power should be adjusted to return the aeroplane to the desired flight condition. Straight and level flight should then be established with full co-ordinated use of the controls. The airspeed indicator or tachometer, if installed, should never be allowed to reach their high-speed red lines at anytime during a practice stall.

As you can see the correct sequence is defined. There is more to flight training than Flight Test Standards.

[MichaelP]

This brings forth a related issue and that is proper QA testing of schools.
One school on this field does not allow outside examiners to test their students.
The result of this is that standards are not checked by an independent person from time to time and I do not think this is safe.

A school can therefore have a 'bad idea', this is taught to the students, and the examiners, on board with this bad idea pass the students on their flight tests.
As I wrote, there are many lessons that have been learned since 1912 and best practices are well established. It's not a good idea to revisit what has been learned to be dangerous over the past 100 years.

[767]

I can quote Transport too:

........The next step in recovering from a stall is to smoothly apply maximum allowable power to increase the airspeed and minimize the loss of altitude. As airspeed increases and the recovery is completed.............

So after all, it does say "power" is used to minimize altitude loss.. (modi13?)...

Thanks for posting this flaplessdork.

I think it would be a good idea if TC can add this paragrapgh to the FTG.

There is more to flight training than Flight Test Standards.

[/quote]

That is 100% true and i agree.

[modi13]

So after all, it does say "power" is used to minimize altitude loss.. (modi13?)...

Yes, but I explained this. You can minimize your rate of descent by only adding power, but you can't level off until you're flying again, i.e. unstalled. That's why the first step, which you cut off, is to lower the angle of attack below the critical A of A and get the wings to produce sufficient lift to allow the aircraft to fly again. You still haven't explained the aerodynamics behind your recovery technique, and since you still seem to be advocating it after I explained why the aerodynamics of it wouldn't work, I'm led to conclude that you have no idea how an aircraft flies or what happens at the stall.

[FlaplessDork]

So after all, it does say "power" is used to minimize altitude loss.. (modi13?)...

Yes, but I explained this. You can minimize your rate of descent by only adding power, but you can't level off until you're flying again, i.e. unstalled. That's why the first step, which you cut off, is to lower the angle of attack below the critical A of A and get the wings to produce sufficient lift to allow the aircraft to fly again. You still haven't explained the aerodynamics behind your recovery technique, and since you still seem to be advocating it after I explained why the aerodynamics of it wouldn't work, I'm led to conclude that you have no idea how an aircraft flies or what happens at the stall.

I can explain the aerodynamics of adding power first. While pulling back on the control column and adding power you're blowing more slipstream at your tail, increasing the airflow over the elevator, thereby increasing the elevator and trim's effectiveness. This in turn cause the airplane to pitch further, increasing the angle of attack, deepening the stall, reducing lift further and dramaticly increasing drag. Which in turn causes you to loose altitude that much faster. Not to mention the increased assymetrical thrust, procession, & slipstream wanting to yaw the airplane putting it that much faster into a spin. The end result is that you'll probably have an airplane that can't fly anymore, and one less poorly trained pilot in our ranks.

[modi13]

Thanks FlaplessDork; I pointed out some other flaws with adding power first, such as the tendency for some aircraft to pitch up and increase the angle of attack. What I meant was for him to explain his theory. How can adding power help to get the aircraft unstalled?

[FlaplessDork]

Thanks FlaplessDork; I pointed out some other flaws with adding power first, such as the tendency for some aircraft to pitch up and increase the angle of attack. What I meant was for him to explain his theory. How can adding power help to get the aircraft unstalled?

We all know it doesn't and he is teaching a dangerous method. He's just to proud to admit he's been wrong all along. People gotta get it in their head that being wrong is not a bad thing if learn from it.

[767]

What both of you say is true. But if you add power, you must lower the nose. If you dont, then what you just described will happen. In the beginning, the argument was about what should be done first (nose down or power). I said power first, where you said nose first. As i saw, everyone here said lower the nose first. So i agree, lower the nose first. But even if you lower the nose first, make sure you add power!!

[Shiny Side Up]

I hate to harp on the subject, but I feel that this really needs to be rectified one way or another. Going back a bit 767 you posted this:

Not only that, power also helps reduce the rate of descent. My student stalled once in a 152, it was a dual flight. If I delayed the power, i wouldve crashed. It was power first, then nose down.

I'm really interested in the circumstances under which this occured. There are few places in flight training where the student has opportunity to be near the ground and wants to pull the nose up. There are two places I can think of off hand which would be common given the training syllabus for the PPL. From the story I would almost say that this was possibly the cathartic moment when you decided to change your training methods in relation to stall recovery. I find it really hard to believe that you were taught this and it wasn't corrected all the way through your PPL and CPL training - unless as MichaelP speculates that you've only had one instructor who also happens to be a class one and a DFTE as well. I hope someone from TC sees this thread and puts out a notice to watch for this to all the DFTEs in the area and especially any of the instructor examiners.

Given your tone here, I personally don't believe that you will make an honest change to your methods. It could be though that the purpose of your life will be to serve as a warning to others. It will be most unfortunate since this will also mean the wrecking of a perfectly good airplane, and even more so if you take other lives with you.

[modi13]

What both of you say is true. But if you add power, you must lower the nose. If you dont, then what you just described will happen. In the beginning, the argument was about what should be done first (nose down or power). I said power first, where you said nose first. As i saw, everyone here said lower the nose first. So i agree, lower the nose first. But even if you lower the nose first, make sure you add power!!

Look at it this way: assume that it takes three seconds to add full power, and three seconds to lower the nose and unstall the aircraft. Before adding power you're descending at 1000 fpm, or ~17 fps, and after you're descending at 800 fpm, or ~13 fps. That means that the total altitude lost = 3(17) + 3(13), or 90 feet. If you add power after you've broken the stall and begun to accelerate, then the amount of time required to bring the power up is included in that required for accelerating; once you've broken the stall and returned to flying speed, power can be used to climb, not just minimize altitude lost. Then the altitude lost during the recovery becomes 3(17) alone, or 51, which is a little over half that required using 767's method. This doesn't even take into account the aerodynamic problems that arise.
I'm not so concerned with the fact that you said that we're right, 767. This thread has revealed a much larger and more disturbing issue: a senior instructor who doesn't understand stalls, and is afraid to teach the recovery properly. As far as I can tell, your reason for advocating the addition of power first is based purely on emotion, without a rational explanation. If you can't explain it, you shouldn't be teaching it. Aviation should never be about subjective judgements, and if you don't have a reason for teaching it that way other than that lowering the nose at low altitude is counterintuitive, should you really be instructing? You've accepted our method, but you still don't seem to understand why it's preferred. If you can't explain the reasoning behind it to a student, then all you have is an argument from authority, which will ultimately be rejected, and will undoubtedly result in the student questioning your knowledge level.

[trampbike]

Well, maybe its becuase the "snap" rolls, spins, etc. arent happening on the flight test(s) during the recovery??

That is the very least... You can do a whole lot of stupid things in a 172 before getting in trouble. But even if it did not snapped on the flight tests, the examiners should still have noticed the bad procedure and freaked out a little bit. This is why everyone is kind of worried.

[apstraining]

Hi All,

I think this is a very interesting discussion with lots of informed instructors participating. In stall recovery, it is important to emphasize reducing angle of attack as the very first step. To reduce angle of attack the elevator must be pushed forward (from the perspective of the pilot in the cockpit) irrespective of flight attitude in a positive angle of attack stall (this is a slightly different concept in comparison to 'lowering the nose' which isn't technically incorrect in a somewhat upright flight attitude). As has been very aptly highlighted by the other instructors in this forum, power on its own is not directly related to solving the stall. It is important for pilots to understand that a stall is an "out of control" flight condition. Before altitude loss can be effectively addressed in any stall, the stall itself must be resolved through the reduction of angle of attack below critical to 'regain and maintain control' of the aircraft prior to addressing the minimization of altitude loss. Here is an interesting article on All-Attitude Upset Recovery strategies that comprehends stall recovery.

I hope these comments added something of value to the discussion.

[AEROBAT]

Welcome to Avcanada Paul! I am sure many people here can benifit from your years of experience in giving upset recovery training. Your Transfer of Skills Concept article points out how the use of primary flight controls is very much the same regardless of type of aircraft being flown to recover from unusual attitudes.

I think everyone will find your contributions interesting.

[trampbike]

A few days ago, I had to deal with my very first stall close to the ground. Hopefully it was the first and the last one. I felt it would be a good idea to bring that old thread up.

I was practicing, as usual, short field landings, in a Grumman AA1, flying at high angle of attack, power-on, a couple knots above stall. Actually the stall warning is singing pretty often when I practice these approach. That time though, when coming close to the runway threshold, there was a sudden wind reduction and the airplane dropped very fast, with the stall warning screaming. I pushed the nose down even though the ground was rushing at me and opened the throttle fully. The recovery took place about 20 feet AGL.

I obviously was getting myself out of my comfort zone doing such approaches, and being a low timer with basically no experience, it was not a good idea, even though I felt confident in my control of the airplane (having practiced of course at higher altitude before).

I just wanted to say that by reading a lot and being told again and again to reduce the angle of attack FIRST when stalled, I did not break the airplane and was unharmed. Would I have opened the throttle first, that little Grumman would probably have flipped on his side.

[niss]

Good advice, glad it went well for you!

[mashowski]

Pull all the way back on the control yoke and hold it there.
Close your eyes before you hit the ground and hope for the best.

[cgzro]

I was practicing, as usual, short field landings, in a Grumman AA1, flying at high angle of attack, power-on, a couple knots above stall

The idea of flying right at the stall with a near 100% fataility probability if a mistake is made v.s. overrunning a strip with a near 0% fataility probability if a mistake is made shows very poor understanding of the relative risks involved.

Proper understanding of the relative risks would have you either pick a longer strip, or prefer the risk of an overrun.

Infact I cannot think of any conditions where stalling a plane at a few hundred feet is the preferred risk.

[mcrit]

I was practicing, as usual, short field landings, in a Grumman AA1, flying at high angle of attack, power-on, a couple knots above stall. Actually the stall warning is singing pretty often when I practice these approachs.

Does the POH list a short field procedure? I'm pretty sure that the one you are using is going to get you killed sooner or later. I'm not saying that to be a smart ass or to take a dig at you; I'm just making a simple statement of fact (one supported by your close call).

[trampbike]

@ cgzro and mcrit, you are absolutely right. As I said, it was not a good idea, not at all! The fact I did this approach often in the past with success is surely is not a proof that it is safe to do so!

Mistake done, aircraft saved, lesson learned. Hope someone else learns from my stupidity.

[Hedley]

For a short field approach, I might suggest considering the following speed over the threshold:

1.2 x Vso

where you have corrected for weight and CAS/IAS.

[Big Pistons Forever]

As the owner of a Grumman AA1B I am puzzled why anyone would feel the need to get slow on approach in this airplane. Power off it glides like a greased brick and a normal appraoch speed will comfortably get you into any runway that is long enough for a safe takeoff.

Another thing to think about is the danger of establishing high sink rates at low airspeed in low powered aircraft. There may not be enough power to arrest the sink rate before you hit the ground.

[trampbike]

I was somewhere between 60 and 65 kias. Vso at max gross weight is 56, and I was alone in the airplane with only half fuel. So it was pretty close to 1.2 Vso.

However, it was a stupid thing to do. It's a good thing you are all telling me that. I'm now waiting for your comments/advices on the subject of overconfidence here viewtopic.php?f=3&t=65250

[PHD]

I am shocked

God Help us.
I am sorry but if an F/O or a candidate on a PPC ride or a student back in the day in Flight training pulled this stunt on me on a stall recovery,
They would have gotten 5 across the eye, followed by "I have control Son"
Consider teaching it the right way not what you are or aren’t comfortable with.
If you aren’t comfortable teaching an exercise, correctly the way it is suppose to be tought. Then you may require some further training with a Class I to help you gain the confident and the skill, along with the proficiency required to pass it on to your students in the proper manner.

1. Is you CFI aware of you teaching stalls the way you do?
2. Have your students on their Flight test been demonstrating stall recovery the way you have mentioned it on this forum?
If the Answer to the previous two questions are yes then:
God Help us.

Do me a favour, if you dare to do a renewal ride for your next Instructor renewal. Teach and demonstrate stalls to the examiner the way you mention it on this forum and let me know how that works out for you.

Nothing else to say

[PanEuropean]

I realize that this discussion has mostly focused on ab initio training, however, Transport Canada recently revised an Advisory Circular concerning stall recovery to Business and Commercial aircraft operators - perhaps the contents of this AC may be of interest. I believe that the contents of this AC were revised to comply with one of the recommendations arising from the report on the Colgan Dash-8 accident at Buffalo, NY.

Here is the link: Training and Checking Practices for Stall Recovery.

Michael