Turbulence Technique advice...help?

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Derek Guiliano

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Took over a student who had three other instructors before me. I have been flying for 10 years, training for 4, and this student started using a technique in turbulence I have never heard of nor been taught to us.

He began to use rudder, and only rudder, to keep wings level. My initial instinct was to tell him not to do that, but after asking him where he heard about this technique from, he said from two of his previous instructors. He was told the reason for it is because it's easier on passengers. While I don't necessarily agree with that because it's much more nauseating to be jossled from side to side than it is to roll, I want to be able to explain it more technically to him as to why, if this is the case, not to do this.

My initial thought is doing so could end up causing oscillations back and forth, eventually leading to and upset attitude recovery situation. The other thought is that by doing so will also cause excessive g loading on the horizontal stab possibly causing damage. All of my training and experience has been to allow the bumps to happen, react after, roll wings level, keeping coordinated.

Is this rudder technique something different that I have just never been taught, or is this a very wrong technique for the thoughts I just said?

Thanks all.
 
I've never heard of using only rudder during turbulence. I just follow what the FAA recommends. Slow to Va, maintain constant attitude and ride the waves.
 
Passengers in the backseat feel every bit of uncoordinated flight. Not sure how rudder only would be easier on them..?
 
Lots of different kinds of turbulence make lots of different responses. Lifting a wing with rudder is not a problem and may be a good response as long as it's gentle. Probably best reserved for slower speeds.
 
I've also heard instructors teaching this. I don't. Coordinated flight is appreciated wherever possible. I don't know where it comes from, but it goes against common sense.
 
CC268 said:
Holy cow that ripped the vertical stabilizer off? Scary
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That accident really changed how people view Va too. A lot of assumptions that had been oversimplified in training to the point where the understanding of turbulence penetration had gotten to be all wrong...
 
That doesn't sound right at all, I've always only ever used rudder to keep coordinated and to slip if needed. Frankly, using rudder excessively in turbulence seems nauseating, leads to uncoordinated flight (which is not what you want ever) and puts unnecessary load on the stab

I just slow if needed and let the plane ride the bumps, using gentle (but firm and steady) inputs to keep level. I try not to fight it as that makes it worse
 
denverpilot said:
I've also heard instructors teaching this.
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Some people teach crazy things. I had a guy "show me a cool trick" once by flapping the rudder left and right to add drag to help drop us in on a short approach. I only had a few hours, no PPL yet. Needless to say I stopped flying with him
 
Tantalum said:
Some people teach crazy things. I had a guy "show me a cool trick" once by flapping the rudder left and right to add drag to help drop us in on a short approach. I only had a few hours, no PPL yet. Needless to say I stopped flying with him
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"Hey, let me show you the world's crappiest S-turns!" LOL.
 
To the OP, what type of plane had your student previously been flying?

To the rest of you, you've seriously never been taught to use rudder to pick up a wing? That's flight control 101 in some popular small airplanes.
 
Use of rudder to bring up a wing is one thing, in concert with aileron. Constant oscillation of the rudder only to correct for constant turbulence is entirely different. It's a pa28-180.

Thanks for all the heads up guys.
 
When slow using rudder to lift a wing is the correct thing since aileron may lead to a stall. It sounds like your student probably got more information than he was able to process and mixed some of the control advice. You're the instructor. Teach.
 
Thanks stewart. Oh yes, slow then use rudder, but this is anything but slow. Talking 100mph in turbulence and doing this technique. Not right.
 
Ryanb said:
Passengers in the backseat feel every bit of uncoordinated flight. Not sure how rudder only would be easier on them..?
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True. One of my students took his wife along on one of our flights. I told her to whack him in the head every time she felt her butt slide sideways. Best coordination lesson I ever gave.
 
Stewartb said:
To the OP, what type of plane had your student previously been flying?

To the rest of you, you've seriously never been taught to use rudder to pick up a wing? That's flight control 101 in some popular small airplanes.
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Yes, when in slow flight or upset recover....
Not in turbulence, or in a back and forth motion.

Tim
 
Stewartb said:
When slow using rudder to lift a wing is the correct thing since aileron may lead to a stall. It sounds like your student probably got more information than he was able to process and mixed some of the control advice. You're the instructor. Teach.
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I actually had an old instructor tell me the same thing. It is an OWT of over simplified instructions.

Tim
 
midlifeflyer said:
True. One of my students took his wife along on one of our flights. I told her to whack him in the head every time she felt her butt slide sideways. Best coordination lesson I ever gave.
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That is awesome!

Tim
 
Derek Guiliano said:
Thanks stewart. Oh yes, slow then use rudder, but this is anything but slow. Talking 100mph in turbulence and doing this technique. Not right.
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Tacking on to @Stewartb's comment, that's still where it might have come from.

One of the reasons taught for slowing to a turbulence penetration speed is to allow the airplane to stall before it breaks. So, now, we are in the "near the stall" world, and I can easily see the instructional disconnect. And, that it could have been the other instructors' disconnect rather the student's.
 
midlifeflyer said:
Tacking on to @Stewartb's comment, that's still where it might have come from.

One of the reasons taught for slowing to a turbulence penetration speed is to allow the airplane to stall before it breaks. So, now, we are in the "near the stall" world, and I can easily see the instructional disconnect. And, that it could have been the other instructors' disconnect rather the student's.
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Va is nothing like stall speed on any plane I have been on.

Tim
 
Stall speed? What's that? I've had my plane momentarily stall at Va in turbulence. The scary thing about that is at the time I believed Va was my safeguard from structural damage, not that I was making any big control movements. I've learned since that Va has little to do with structural safety and turbulence penetration. That goes back the the airliner and the full rudder deflection investigation summary. Until then I never knew what Va was other than what instructors had told me.
 
tspear said:
Va is nothing like stall speed on any plane I have been on.

Tim
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Really? The published "stall speeds" in the book are for a series of specific configurations, various bank angles and flap settings, but all of them in unaccelerated, coordinated flight (the white arc only covers two of them - level, coordinated flight, flaps up and flaps all the way down). The difference is load factor. What turbulence does is change load factor precipitously and stall "speed" changes as a result.

Like
Stewartb said:
Stall speed? What's that? I've had my plane momentarily stall at Va in turbulence
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I have also heard the stall horn during cruise in turbulence at Va (or Vb - I won't get into that discussion, but that's why I referred to "turbulence penetration speed" before).

Haven't you?
 
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Yeah, do remember that stalls can happen at any airspeed, and rudder usage to correct a wing drop when near or at a stall is correct, but at normal airspeed not in a stall should only be used for coordination
 
Derek Guiliano said:
Use of rudder to bring up a wing is one thing, in concert with aileron. Constant oscillation of the rudder only to correct for constant turbulence is entirely different. It's a pa28-180.

Thanks for all the heads up guys.
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A PA-180 has really good differential ailerons, so that technique is not appropriate, imo. The book Stick and Rudder explains how to use rudder properly in turbulence to pick up a wing, pg 235: "...for proper flying in a conventional airplane, rudder must always be used when the ailerons are used, even if the ailerons are used only to counteract a gust."

dtuuri
 
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midlifeflyer said:
Really? The published "stall speeds" in the book are for a series of specific configurations, various bank angles and flap settings, but all of them in unaccelerated, coordinated flight (the white arc only covers two of them - level, coordinated flight, flaps up and flaps all the way down). The difference is load factor. What turbulence does is change load factor precipitously and stall "speed" changes as a result.

Like

I have also heard the stall horn during cruise in turbulence at Va (or Vb - I won't get into that discussion, but that's why I referred to "turbulence penetration speed" before).

Haven't you?
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Stop changing the topic. You stated "Va is like stall speed", hence why the student confused what the instructors have stated.
I simply said, that Va and stall speed have never been in near each other, or similar on any plane I have flown.

Pick a plane, and publish the Vso and Va speeds. Then explain how the configuration differences, speeds and techniques are similar enough for someone to confuse.

Tim
 
Stewartb said:
To the rest of you, you've seriously never been taught to use rudder to pick up a wing?
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Sure, but that's during slow flight or near stall speed. Pumping it left and right in turbulence without aileron seems crazy
 
tspear said:
Stop changing the topic. You stated "Va is like stall speed", hence why the student confused what the instructors have stated.
I simply said, that Va and stall speed have never been in near each other, or similar on any plane I have flown.

Pick a plane, and publish the Vso and Va speeds. Then explain how the configuration differences, speeds and techniques are similar enough for someone to confuse.

Tim
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Sorry, but your post still sounds like there is only one "stall speed" that is dependent on "speed" rather than on "load factor." That "confusion" - thinking that stall speed is a not-dependent-other factors IAS (or CAS) is a major problem in the current FAA "loss of control" hot topic.

Whether your view of it or mine is more helpful is for others, not us.
 
midlifeflyer said:
Sorry, but your post still sounds like there is only one "stall speed" that is dependent on "speed" rather than on "load factor."
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If you want to be technical, load factor has nothing to do with it. Angle of attack to the relative wind is the key, this determines when the airflow will separate from the boundary layer and lose lift. The exact manor in which the boundary layer dissipates and the airflow separates from the wing surface changes based on the airfoil selected.
Now with that technical crap out of the way.
Each and every plane in the good ol' USA has a published stall speed, and many include a maneuvering speed, often referenced as "penetration speed" although this is incorrect. These two speeds are taught to students, along with the speeds taught, the configuration is taught at the same time.
No plane I have ever flown, or read the POH/AFM for has had a stall speed or a maneuvering speed which are at all close to each other in any way. Configuration, speed, control usage...
So going back to your point that the student is confusing the two, I am saying BS. I have had an old instructor tell me the same thing, use rudders in turbulence because it is safer, better for the passengers, and will not break. Depending on the plane, and passenger seating, it may be better for the passengers; not likely, but theoretically I can see how. As for the rest of the claim, it is complete BS.

Tim
 
tspear said:
Stop changing the topic. You stated "Va is like stall speed", hence why the student confused what the instructors have stated.
I simply said, that Va and stall speed have never been in near each other, or similar on any plane I have flown.

Pick a plane, and publish the Vso and Va speeds. Then explain how the configuration differences, speeds and techniques are similar enough for someone to confuse.

Tim
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They don't have to be near each other, but Va IS a "stall speed"...it's the maximum speed at which the airplane will stall before it's over stressed with a control deflection. It's often used as a turbulence penetration speed (see Mark's allusion to Vb being the correct speed) because it's the max speed at which the airplane will stall before it's over stressed by a vertical gust.
 
MauleSkinner said:
They don't have to be near each other, but Va IS a "stall speed"...it's the maximum speed at which the airplane will stall before it's over stressed with a control deflection. It's often used as a turbulence penetration speed (see Mark's allusion to Vb being the correct speed) because it's the max speed at which the airplane will stall before it's over stressed by a vertical gust.
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Um no it is not. Maneuvering speed is the max speed for which a you can do full deflection of the controls in a single direction and NOT break the airplane. That is all it is.
https://www.avweb.com/news/features/The-Risks-of-Maneuvering-Speed-Myths-222680-1.html

AC 23-19A states:
48. What is the design maneuvering speed VA?
a. The design maneuvering speed is a value chosen by the applicant. It may not
be less than Vsv n and need not be greater than Vc, but it could be greater if the applicant
chose the higher value. The loads resulting from full control surface deflections at VA are
used to design the empennage and ailerons in part 23, §§ 23.423, 23.441, and 23.455.
b. VA should not be interpreted as a speed that would permit the pilot
unrestricted flight-control movement without exceeding airplane structural limits, nor
should it be interpreted as a gust penetration speed. Only if VA = Vs vn will the airplane
stall in a nose-up pitching maneuver at, or near, limit load factor. For airplanes where
VA>VSvn, the pilot would have to check the maneuver; otherwise the airplane would
exceed the limit load factor.
c. Amendment 23-45 added the operating maneuvering speed, VO, in § 23.1507.
VO is established not greater than VSvn, and it is a speed where the airplane will stall in a
nose-up pitching maneuver before exceeding the airplane structural limits.


Tim
 
Huh? You say Va is the max deflection speed and then link an article that says the opposite???
 
Stewartb said:
Huh? You say Va is the max deflection speed and then link an article that says the opposite???
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Nope. Read the article, specifically section on FAR Part 23.

Tim
 
Va is the airspeed at which if full and abrupt movement of the controls are done, the aircraft will stall before cussing structural damage. In a manner of speaking, it is a stall speed, but not in the traditional sense of a demonstration stall. If anything, it's acceleration stall speed, but again, even that's a misnomer. Va is and is not a stall speed, but I do not teach it as a stall speed, I teach it as a speed to not exceed in other than smooth air.
 
Derek Guiliano said:
Va is the airspeed at which if full and abrupt movement of the controls are done, the aircraft will stall before cussing structural damage. In a manner of speaking, it is a stall speed, but not in the traditional sense of a demonstration stall. If anything, it's acceleration stall speed, but again, even that's a misnomer. Va is and is not a stall speed, but I do not teach it as a stall speed, I teach it as a speed to not exceed in other than smooth air.
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Where is it defined as a stall speed? I am asking for where instructors have taught it as stall speed, but where in the regulations or AC guidelines is it defined as a stall speed?

Tim
 
Derek Guiliano said:
Va is the airspeed at which if full and abrupt movement of the controls are done, the aircraft will stall before cussing structural damage.
Click to expand...

This is what many have been taught and what some books say...but unfortunately it is not a true statement in its entirety.

A better statement might be: Va (adjusted for weight) is the airspeed at which if a single full and abrupt movement of a single control is done, the aircraft will not be structurally damaged.
 
Derek Guiliano said:
Va is the airspeed at which if full and abrupt movement of the controls are done, the aircraft will stall before cussing structural damage.
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This is the exact problem with over-simplifying when teaching.

Is the rudder a control? Will full and abrupt movement of the rudder cause a stall at Va?

How about the ailerons?

Your phrase is also how I originally learned Va. I later learned it's flat wrong. And at best, misleading.

It also dangerously suggests a pilot technique for turbulence that it shouldn't. (That full and abrupt control inputs are "ok". They're not. This should be obvious via common sense, but this phrase about Va won't go away.)

You'll probably change how you teach it, after you look up how it's defined during certification. Not a single thing in the definition of Va about control deflection.
 
Clark1961 said:
This is what many have been taught and what some books say...but unfortunately it is not a true statement in its entirety.

A better statement might be: Va (adjusted for weight) is the airspeed at which if a single full and abrupt movement of a single control is done, the aircraft will not be structurally damaged.
Click to expand...

I like your better statement.

I was taught just a few years ago that flying below “maneuvering speed” broadly protected the plane from structural damages due to full and abrupt movement of the control surfaces. However, as crystalized in your statement, that's not quite right. This 2010 rulemaking statement from the FAA says what I was taught is potentially misleading without some important qualifications:

"The NTSB found that many pilots of transport category airplanes mistakenly believe that, as long as the airplane's speed is below VA, they can make any control input they desire without risking structural damage to the airplane. As a result, the NTSB recommended that the FAA amend all relevant regulatory and advisory materials to clarify that operating at or below maneuvering speed does not provide structural protection against multiple full control inputs in one axis or full control inputs in more than one axis at the same time."

https://www.federalregister.gov/doc...-20195/maneuvering-speed-limitation-statement
(based on the 2001 American Airlines accident attributed to multiple, full swing rudder deflections)

Another interesting point is Va is supposed to refer to the “DESIGN maneuvering speed,” as opposed to the “maneuvering speed” we’re now talking about. However, because it’s become so ingrained, the FAA continued to allow manufacturers to use Va to refer to “maneuvering speed” in AFMs. Clear as mud.
 
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