A fresh approach needed to wing drop recovery at the stall

[Centaurus]

The RAAF way ever since I got involved with it (early 80s) was to use rudder only to 'prevent further yaw', which practically means use only enough to stop the wing drop, not pick it back up to wings level (which is just asking for an autorotation in my view).

The subject of how to recover from a wing drop at the point of stall was comprehensively discussed in previous posts on this forum. It started with the oft-used term by flying school instructors of "pick up the wing with rudder." In other words if a wing drops at the point of stall, use as much rudder as needed to level the wings but don't use ailerons until the wings are levelled. This rather confused teaching is still rife and one wonders where it originated. The highlighted text is one example of the posts that got it straight.

Bob Tait's Aviation Theory School books are popular because of their easy to read style. That includes his VFR (Day) Basic Aircraft Knowledge study guide for student pilots. On page 5.10 of Issue 17, July 2011, he discusses the use of controls and includes his theory on how to recover from a wing drop at the point of stall.

He writes that student pilots should never use ailerons to pick up a dropped wing at the stall. Further, he states "Do apply opposite rudder to yaw the aircraft away from the roll. The application of opposite rudder is more efficient [to pick up the wing to level flight], because it produces a yaw which accelerates the dropping wing by reducing it's angle of attack."

Over many years, improvements in aircraft design and certification include ailerons designed to be effective below the stall. Yet Bob Tait's BAK book continues to perpetuates the myth of only using rudder to pick up the wing at the point of stall. This flawed teaching detracts from an otherwise well written book. Generations of student pilots and their flying instructors buying their Bob Tait BAK books, will understandably believe this as God's Truth, which in turn explains how this myth continues in flying schools, ad infinitum.

Without detracting from his otherwise excellent BAK book, perhaps the time is long overdue for the author to discard his pet theory on wing drops and amend his text to reflect reality?:ok:

[Frank Arouet]

In quiet a few aircraft like the Piper Colt, Tri pacer, and Maules, the rudders are interconnected with the ailerons via cables. It makes for difficult side slipping and obviously has a bearing on wing drop and pick up with rudder. I think the rudder has most authority though.

[djpil]

I don't think that Bob comes here so I suggest that you post this on his forum and suggest that he amend his text to be consistent with CASA's Flight Instructor Handbook: In addition rudder must be used to prevent the nose of the aeroplane yawing into the direction of the lowered wing. The ailerons should be held neutral until control is regained, when the wings should be levelled.

Over many years, improvements in aircraft design and certification include ailerons designed to be effective below the stall.Improvements in design and certification are not retrospectively applied to existing aircraft in service. Perhaps a cockpit placard identifying the applicable certification standard and an endorsement requiring additional training on types certified to different standards. FAR 23 to Amdt 6 is what I fly generally.
For an airplane with independently controlled rolling and directional controls, it must be possible to produce and to correct roll by unreversed use of the rolling control and to produce and correct yaw by unreversed use of the directional control, up to the time... the airplane stalls.

But that is only for level stalls - any other situation simply requires that the pilot be able to stop it from going into a spin.

Those who want to use aileron to pick up a wing at the stall must stick to airplanes certified to FAR 23 post-Amdt 62. Not many of those around.

Even lots of non-FAR 23 airplanes around still.

[Oktas8]

In addition rudder must be used to prevent the nose of the aeroplane yawing into the direction of the lowered wing. The ailerons should be held neutral until stall symptoms cease, when the wings should be levelled.

In my experience, "control regained" means different things to different things to different people. Pitching stopped? Roll stopped? Aircraft climbing? Regained intended flight path?

Hence the wording as amended above, borrowed from an RAF technique. It is arguably more objective, less open to misinterpretation, than CASA's wording.

[djpil]

I am sure that I would misinterpret "stall symptoms".

[5-in-50]

All we're talking about here is drawing the wrong conclusion from poorly chosen wording. I believe the current GA accepted standard is:
1 - stall occurrence
2 - gently release control back-pressure
2 - apply opposite rudder to the direction of wing drop to counteract the yaw and roll
2 - apply power
3 - now that the stall has stopped (you can tell because the rotation has ceased), execute a balanced roll (rudder and aileron together) to level the wings

There are three number 2's above, as they are simultaneously completed.

[currawong]

I'm with 5-in 50.

Except the third 2 - there may be no power or further power available for whatever reason.

Personally, I think the "old" way is still taught because aircraft that will spin are still being flown.

The average punter may never get in one but they are covered if they do.

Which will possibly be a whole new thread...

[Bankstown Boy]

Back in the days when I were young, doing an initial BE58 endorsement - approaches to stalls at (luckily) 4,000'.

I made the mistake, I knew it was wrong but did it any way, of correcting a small wing drop by applying a correcting aileron input.

Next thing I knew we were inverted, about 30-40 degrees nose down.

Didn't take that much to correct (aside from the at least 1,500' altitude drop) to correct, but I learnt a very valuable lesson from that.

We discussed at length and went straight back upstairs to try it again.

I guess i'm i'm a bit of a fan of rudder vs aileron at the edge of the stall.

I don't pretend to know all of the physics involved, albeit have a pretty good understanding but in a BE58, I can tell you what appears to work and what doesn't from hard, practical experience.

It could well be different in other aircraft but it's not a lesson that has faded from my mind, even after nearly 30 years.

[waren9]

In my experience, "control regained" means different things to different things to different people.

shouldnt do.

control is when the flight controls start working again in the conventional sense

afterall, isnt "loss of control" or "departing controlled flight" when flight controls stop working in the conventional sense?

aerobatics aside

[Ixixly]

As you mentioned Centaurus newer aircraft do indeed retain Aileron Effectiveness further into the stall, but there are, as others have pointed out, the older style that don't. Wouldn't the current idea of using Rudder to counter wing drop be the best method to teach as it covers either aircraft type safely whilst teaching people to use Aileron to counter it could lead them to trying to do so one day in an aircraft that isn't suitable for it?

Maybe sometimes it's better to teach something that isn't entirely accurate but is safer overall? a little white lie? :E

[ShyTorque]

Seeing as you're only trying to stall as a set piece, to practice recovery from it, why try to pick the wing up anyway? I was taught (by the RAF) to unstall first then pick up the wing.

[Centaurus]

I was taught (by the RAF) to unstall first then pick up the wing.

Precisely. Simultaneously lower the angle of attack (forward stick) to unstall the wings, stop further yaw from any downgoing wing by enough rudder and level the wings with coordinated use of aileron. And of course power on to minimise loss of height. Same technique applies to a Tiger Moth and Boeing 737.

[Centaurus]

I don't think that Bob comes here so I suggest that you post this on his forum and suggest that he amend his text to be consistent with CASA's Flight Instructor Handbook:

Thanks for the suggestion. The deed has been done:ok:

[FlexibleResponse]

Bob Tait is correct.

Trying to stop the rolling moment on a stalled wing by using aileron (which effectively increases the AOA on the outboard part of the downgoing wing) is potentially disastrous.

Correct technique is:

1. Control the rolling moment when a wing is stalled with rudder.
2. Reduce AOA.
3. When both wings are un-stalled, use aileron to control roll.

We must differentiate between a stalled wing and an un-stalled wing.

We also need to understand that most modern aircraft have wings that are now designed to stall on the inboard section first to avoid nasty stalling charteristics. And as a result they may retain effective aileron control when the inboard sections are stalled.

That doesn't change the basics of good piloting.

Most old aircraft (and especially warbirds) don't exhibit the flying qualities of modern aircraft during stalls.

Bob Tait is correct.

[Tinstaafl]

I'm with Centaurus. I've never taught to use rudder in a stall recover 'to pick up the wing', not even to use rudder to control roll. Only to prevent *yaw*, so...

1. Pitch to unstall, while simultaneously
2. Rudder to prevent further yaw, and
3. Any power available applied after pitching commenced

Once under control:
4. Roll level with normal coordinated use of controls, and
5. Pitch to minimise altitude loss.

[Skydiveandy]

i am not sure how many of you posting are instructors, I can see a few.. Remember guys, the students that are being trained initial stalling including incipient spins have 5-6 hours total time depending on the syllabus

This is one of the most stressful lessons the students go through. Even the best of the best Instructor has difficulties reducing the fears and anxieties of even the most confident student.

It doesn't particularly matter what wording we use providing we can get the result of ensuring out students is safe if and when they get themselves into trouble.

At 5 hours, do you really think that the full aerodynamic description of what is going to happen is sinking in. I dont.

Keep it simple, especially at that stage.. Use a technique applicable to the type of aircraft being flown, more times than not and old C152,C172 etc etc etc

Most important, where written use the technique published in the POH, later on when the coroners court comes asking you wont have to explain why you taught something different to the manufactures manual.

Just food for thought

[Homesick-Angel]

I think the "pick up the wing" method falls into the aviation bad terminology book, and is yet another one of those terms we use which can be, and are regularly misconstrued.

I'm sure there are instructors out there who do the technique correctly and use the wrong terminology, and visa versa.

You get an idea of the damage that poor terminology can cause when you teach international students, but I think the damage is done to English first language students as well.

Examples: Dashboard/glareshield/instrument panel.

Release BP/relax BP/push forward

Care with words is what will separate a good instructor from the rest, because frankly, in the early stages of training, you are too maxed out to be trying to decipher what the hell your instructor is talking about-to have to translate as well adds to the problems.. In my experience, the best instructors don't say a lot, but when they do its invaluable.

As has been previously mentioned, using aileron while the wing is dropping will inflate the situation (although the stall characteristics of your average trainer are benign to the point of being able to do almost everything wrong and still recover as long as you have altitude.) The rudder at this point is to stop the yaw and roll, the stall is broken by relaxing back pressure, and then once control is regained you can use aileron, give it the jets and climb away.

The thing is, if you do nothing more than just use rudder and relax BP, what do you think will happen as the airspeed builds? Perhaps this is what flames the fire if this method?

My final point on this is I think anxiety plays a role in stall recovery. I'm surprised how many experienced pilots can show many symptoms of anxiety anywhere near the stall. Sadly, I think there are instructors out there who feel the same way, and this is just a lack of experience and possibly a true understanding of the stability and durability of the trainers they are in?

If you get a chance, climb to. 4500 do your pre stall checks and fly around S+L with the stall warning on the whole time. Climb and descend doing the same thing. Apart from everything being a bit sluggish, the aircraft is still flying quite well, and you will also get an appreciation of the effect of rudder vs aileron at these speeds.

Notice how much forward movement is required to stop the stall warning. Depending on what your flying, if it's more than an inch or two I'd be surprised.

[The Green Goblin]

Coordinated ruddrr to prevent further yaw, never to pick up a wing (in light aircraft). Or opposite rudder to have some fun :)

In my current type,

Nose down pitch control apply
Bank wings level
When out of the stall:
Thrust increase smoothly as needed
Speed bakes check retracted
Flight path recover
If in clean config and below FL200
Config 1 select

[training wheels]

In my current type,

Nose down pitch control apply
Bank wings level
When out of the stall:
Thrust increase smoothly as needed
Speed bakes check retracted
Flight path recover
If in clean config and below FL200
Config 1 select

.. and if only the crew of AF447 had followed the above technique too .. :ouch:

[djpil]

Another phrase I don't like is " full back pressure" - no-one has ever responded when I ask what it means.

[dubbleyew eight]

I also think/know that bob tait is correct.

the picking up of a wing almost at the point of stall was an exercise in aircraft control that improved one's confidence in slow speed handling.

the cessna 150 and the cessna 152 do it superbly.

aileron input to neutral and walk it along using only rudder inputs to control the wing attitude.

centaurus just because you have an idea, or because it was done a particular way in the RAAF doesnt mean you are correct.

[Horatio Leafblower]

Deleted due good points made later about stick position

[Fantome]

The late Ron Pill at the Canberra Aero Club was the good fella who introduced me to stalling in the Chipmunk. The syllabus followed was out of the RAF manual (AP129 in might have been). Rudder to correct wing drop first.
On recovery and regaining control , power was applied only when the nose came up to the horizon.

The GFA practice of teaching stall and spin recovery straight out of the manual has been there since year dot. Glider pilots do tend to be particularly aware of their margin above stall speed round the circuit and down to the approach threshold.

FUST flaps - u/c - speed - trim are the essentials

(lest the ground rise up and smite thee, brother.)

[A37575]

the picking up of a wing almost at the point of stall was an exercise in aircraft control that improved one's confidence in slow speed handling.

the cessna 150 and the cessna 152 do it superbly.

aileron input to neutral and walk it along using only rudder inputs to control the wing attitude

You can do exactly the same thing by using only the aileron and keeping rudder centred. You can also turn a Cessna by opening one door into the slipstream and it does a nice rate one turn. You can also keep the control column neutral and cause the nose to climb or descend by varying the power. All of which has nothing to do with the purpose of the original post

[Dora-9]

Fantome:

On recovery and regaining control , power was applied only when the nose came up to the horizon.
With respect, that certainly wasn't what the RAF was teaching. AP.101B-5510-15 (formerly AP.4308A-PN) entitled Pilot's Notes Chipmunk T. Mk. 10 dated 3rd June 1966 states:

"To recover with minimum loss of height, apply full power and, simultaneously, move the control column sufficiently far forward to unstall the aircraft. Use rudder to prevent any further yaw. When control is regained, level the wings with aileron and ease the aircraft out of the dive."

[Oktas8]

Another phrase I don't like is " full back pressure" - no-one has ever responded when I ask what it means.

Full back pressure is fun though - move the controls briskly to the aft stop. Then watch the fun!

My pet hate djpil is "relax back pressure". In the context of stalling in the real world, I like to assume that the elevator trim could be in any position at all, including full nose up.

Hence my (plagiarised) phrase "move the control column forward until..." Relaxing a control column force implies a sedate stall in S&L in the training area. Not real world at all.

[djpil]

I agree - "relax back pressure" is too casual a thing to say for an emergency action.

Sure it can be fun to move the stick briskly to the aft stop - doesn't need FULL back pressure in the aeroplanes that I fly. FAR part 23 places no numerical limits on the elevator stick force in maneuvering flight other than to say (23.143) that the force on the pitch control should never exceed 60 Ibs ( s t i c k ) or 75 Ibs (wheel) during temporary applications or
10 Ibs during prolonged applications. I guess that defines full back pressure?
.... reports that, for some of the light aircraft investigated, stick force gradients varied between 8 and 17 Ibs per g for speeds of less than
100 knots.So, I might easily get full back stick with only 20 or 30 lbs depending on what I am flying?

Point is that pilots sense stick force rather than stick position but much of the time it is stick position that matters .... matters so much more.

(Technical reference above is NASA CR-1975 Riding and Handling Qualities of Light Aircraft.)

[Jack Ranga]

Pilots are the coolest dudes, they know everything!

I like NASA, they actually spend money (or used to) on research & employ pilots that aren't full of themselves. They don't perpetuate OWT's.

[Judd]

"Pilots are the coolest dudes, they know everything!"


Dead right about that. A student pilot told me that his grade 3 instructor told him that wing drops depend on wind direction. If the wind is from the right the right wing will drop at the stall and vice verse for the left wing. Interesting theory?

[43Inches]

What really needs to be understood is what is causing the roll to happen. If the aircraft is rolling due to the effect of yaw then rudder is most appropriate, if it is rolled and is not or no longer yawing then coordinated aileron would be better.

In a modern basic trainer I instructed in not so long ago applications of power at low speed caused an apparent large roll to the left, of course it was yaw induced. If power was applied at low speed near the stall the students would tend to try to roll level with aileron which would have no effect or make the situation worse. Obviously coordinated use of rudder primarily and aileron to keep the aircraft level was needed, but not so obvious to the students until it was hammered into them. A slow speed pattern was developed particularly to enhance low speed handling and coordination involving very low speed level, climbs, descents and climbing/descending turns with power varying though-out to maintain specific speed, headings and rate of climb/descent.

In most training Piper and Cessna and other low powered types the designs allow for lazy footwork at low speed until you are right at the stall. Then at the stall particularly in the Cessna the aircraft would yaw and roll away if uncoordinated.

As far as the back-pressure issue, the PA28 has an anti-servo tab which gives induced feedback to the pilot based on servo position with virtually no feel coming from the stabilator itself without. This also means that it will oppose any force input at a greater rate the further you move the control from the trim position. This combined with trim change from no to full power could result in a serious nose pitch up without significant opposing forward force.

As has already been covered;

Apply forward movement of the control to achieve a nose down pitch change, until aircraft is unstalled.

Correct any yawing motion with rudder. (step on the ball/away from the string etc...)

Once back to coordinated flight maneuver aircraft back to desired state using normal control inputs.

If minimum height loss is desired then smoothly apply power and climb away.