Wing drop at stall

[UAV689]

thoughts on instructing students to stop a wing drop at stall with rudder?

i personally think its the wrong thing to do. A wing has stalled, so just do the standard stall recovery.

Wing drop is taught as a symptom of stall, so just do the SSR at that point.

Besides, if i want to spin intentionally, I tend to do it by rudder at the stall...! And who knows in heat of moment what direction of rudder they will put in if an instructor is not there...

[spekesoftly]

The thread linked below is from many years ago, but you might find it interesting:-

http://www.pprune.org/flying-instructors-examiners/13587-wing-drop-stalls.html

[Kemble Pitts]

Current instructor training is to teach students to unstall the wing (stick forward, enough) whilst adding full power. Once the aeroplane is flying again, only then sort out the roll.

I'm with you on the spin risk, although it is often over-stated, but even so.

Out of interest, current aircraft certification requirements actually demand that the ailerons are fully effective all the way into the stall. However, older aircraft (pre-1960s) might not be so amenable so I think its best to teach students to stay off the rudder and ailerons altogether until the aeroplane is flying again.

[Big Pistons Forever]

All ab initio stall training should start with the understanding that the point of the exercise is not to teach you how to stall the airplane, it is to teach you how to recognize the aircraft is about to stall and fix the situation before it does stall. However if you are asleep at the switch then it is important that you learn how to quickly regain control. This should always start with reducing angle of attack by smoothly but firmly lowering the nose and then applying full power. Control of yaw at this point now becomes important as if the aircraft is allowed to yaw then it can spin. Effective use of the rudder is the way to control yaw and thus eliminate the possibility of the aircraft departing in a stall.

Even though modern aircraft certification standards require that the ailerons be effective even after the wing has started to stall, ailerons should still not be used to level the wings until the aircraft is definitely un-stalled

The biggest problem I see with ab initio instruction is the exercise is taught with the aim of generating a good mark on the flight test, instead of showing students the real world scenarios that pilots get into trouble on.

[Whopity]

by smoothly but firmly lowering the nose
That may be the consequence of what you do, but the correct teaching is to move the control column centrally forward. That may or may not lower the nose.
The rudder is used to prevent further yaw

[Genghis the Engineer]

Hopefully you can open this, which was a fairly extensive research into optimal recovery actions.

https://www.aerosociety.com/Assets/Docs/Protected/Subscribers/AeroJournal/3965.pdf


If that didn't work, try this link:

https://bura.brunel.ac.uk/bitstream/2438/10015/2/Fulltext.docx

It didn't actually look into the absurdity of picking up a dropped wing with rudder, which I think most of us know more correctly by the name "spin entry". It concluded that optimal recovery is simultaneous pitch and power in all singles tested.

G

[Whopity]

It was suggested at a FIE standardisation meeting some years ago, by a fairly senior former RAF QFI that the practice of using rudder at the point of stall came from training on the Harvard. When the aircraft dropped a wing, the weight of the engine lead to increased yaw and the use of top rudder in the recovery would minimise the height loss. Unfortunately, this technique was passed on to many new instructors, who were trained in the 60s by FIC instructors who might have been trained on the Harvard.
Following a rather nasty accident in a Slingsby involving "oscillatory stalling" the practice of trying to pick up a wing with rudder was discouraged by the CAA.

[Genghis the Engineer]

Given the Harvard's well known reputation for spinning off a stall, particularly if inadvertently stalled in the final approach configuration - that is "interesting".

I just took a look on the national archives website, but unfortunately can't seem to see any A&AEE flight test reports on the Harvard - it would be really interesting to compare that supposition to the published characteristics of the aeroplane.

I did find this webpage with a set of what appear to be wartime USAF training notes for the Harvard....

https://www.t6harvard.com/pilot-stories-2/1952-basic-flying-air-training-command-manual-pdf/

If you download chapter 5, and go to page 62 you find...

When you recognise the stall, recover by simultaneously apply positive forward stick pressure and opening the throttle to the sea-level stop. Apply rudder pressure as necessary to keep the nose of the aircraft from yawing as it comes down, and aileron pressure, as necessary, to keep the wings level. Normally, additional right-rudder pressure will be necessary to overcome the gyroscopic action of the propeller as the nose is lowered. Allow the nose to continue down to an attitude slightly below the normal cruising speed, straight and level flight attitude.

<snip>

The possibility of a wing dropping during a stall, and the proper corrective action, bears further detailed discussion at this point. Most modern aircraft are so constructed that the wing will stall progressively outward from the wing root to the wing tip.

<snip>

The rudder should be used in such a manner as to prevent the nose from yawing toward the low wing. That is, it should be used to keep the nose attitude straight ahead.

It goes on for several pages after that, but so far as I can see, every mention of the rudder is about either preventing further yaw, or keeping the ball in the middle. It repeats several times what we'd still say now - unstall the aeroplane with elevator, then use the ailerons to roll wings level.

G

[Whopity]

The rudder should be used in such a manner as to prevent the nose from yawing toward the low wing. That is, it should be used to keep the nose attitude straight ahead.
Which could have been misinterpreted to mean pick up the wing with opposite rudder. So many old school instructors taught this that it had to have originated somewhere, with a little bit of "Send three and fourpence, we're going to a dance"

[Genghis the Engineer]

Might have been on some other type? I certainly agree that it's a bad practice anyhow.

What works on a Tiger Moth?

G

[Fl1ingfrog]

We, all too often and unwittingly confuse the central aim of recovery from the stall, with the process. The first aim must be to unstall the wing(s), nothing else.

Applying power will not unstall the wing(s). The rudder will not unstall the wings. In my view it doesn’t matter whether you move the hand control forward centrally or not, what really matters is that you stop holding back.

The aircraft cannot stall on its own; it takes the pilot to do it. So if stalled the pilot must be pulling the control aft. The inherent pitch down moment will be so strong the pilot needs only to relax the back pressure; the aircraft will do the rest. The angle of bank, if any, is irrelevant and should the aircraft be turning, so what.

After unstalling the aircraft and regaining control, then and only then does achieving the minimum height loss becomes paramount. Applying power and levelling the wings is a major part of this of course. Incidentally, with regard to the Harvard an old mentor would regularly refer to how quickly, during stall recovery, you could put a Harvard on its back with too much power if also applied too early.

However, having applied power then control of pitch, roll and yaw will be required with the simultaneous use of all three controls. During the olden days when the CAA had a flight examiner wing an internal argument raged; some saying “the simultaneous use of power and pitch ...” for recovery but this would send others into a state of apoplexy whilst banging the table and demanding hysterically that you must say “pitch and then power...”. The late great Hector Taylor when asked for his view replied: “the simultaneous use of pipowtcher...” was how he said it. He explained that it was the only way he had found to say pitch and power at the same time.

[double_barrel]

The biggest problem I see with ab initio instruction is the exercise is taught with the aim of generating a good mark on the flight test, instead of showing students the real world scenarios that pilots get into trouble on.

Absolutely! It was taught to me purely as a 'task' to be competed without changing altitude or direction. I would like a more real world scenario, eg simulating a slow turn to final in which I am daydreaming, let airspeed fall during the turn and suddenly find myself in a stall with one wing low. I understand that is a common way to die, so it would seem to be worth to build-in the correct instincts for such circumstances.

[Whopity]

It was taught to me purely as a 'task' to be competed without changing altitude or direction. Do you mean to say that you were never taught nor examined whilst stalling in the base turn?

[double_barrel]

Do you mean to say that you were never taught nor examined whilst stalling in the base turn?

Yes. Only from straight and level with varying amounts of flap.

[Kemble Pitts]

GtE

A (properly rigged) Tiger Moth will usually just stalls wings-level withou a wing drop and with a high rate of descent, so unstall the wing and add power and away you go. To be honest, with such a deficiency of aileron its pretty hard to make a Tiger go around a corner anyhow...

On the Harvard you simply unstall the wing, add power and then deal with the (rather large) wing drop. Did that a couple of weeks ago on a re-check ride and it seemd to work just fine.

[Whopity]

db
Yes. Only from straight and level with varying amounts of flap.
May I ask which country you trained in?

A few years ago there was an incident in the UK where a Microlight pilot was killed in an accident following a stall. On investigation, it was found that his Training Records had been falsified and that he had not completed the required stall training. The Instructor received a 6 month sentence.
Every test, club check etc that I have ever conducted has involved stalling in the turn, and you have never done this, it is also one of the major reasons for failure.

[double_barrel]

db

May I ask which country you trained in?.

Not the UK!

[BigEndBob]

I have sometimes been with pilots in their LAA aircraft for the one hour with instructor and say to them lets do some stalls.
Usual reply is, they have never stalled the aircraft.
So i ask them, well how do you know what a safe airspeed is on the approach and landing.
Often they say the previous owner said fly it at a certain (too fast) speed.

Lets face it, if a stall and wing drop occurs, the first thing a pilot will do is probably full opposite aileron.
It will never happen in a clinical practise way.

[Genghis the Engineer]

Exacerbated by the LAA not historically ensuring a properly populated and checked POH! (Although that does seem to be changing with the latest types.)

G

[Kemble Pitts]

Let's be fair to LAA here, you don't need a POH to take your aeroplane up to 5000 ft and see how it stalls clean. dirty, dirty/turning. You need to be taught to fly properly and you'll then understand that stalling is not scary and its a good idea to know how your aeroplane behaves.

When giving people 'biennials' I always get them to stall straight and turning. Most of them gibber when I show them turning stalls (some for stalls of any sort), some actually sweat, and they are often too nervous to really do it themselves with me next to them. I've often had to complete the 'back stick' pull to get the thing to stall as they just can't bring themselves to do it. Maybe that shows a good degree of self preservation but I'd rather they experienced the full stall and practised the correct recovery and made it automatic.

Bottom line is most (GA) pilots are scared of stalling, possibly because most instructors are too. I do my best to overcome this during the biennial '1 hour'.

[dook]

As an ex-RAF QFI, would someone please tell me how to unstall a wing using rudder ?

[Kemble Pitts]

Now, I know you're being facetious Dook, but...

If a wing is stalled you need to reduce its angle of attack to unstall it. Put in a boot full of rudder and you lengthen the forward vector and the AoA of that wing reduces: the wing unstalls. Of course the yaw has the opposite effect on the other wing. I think that is a popular way of entering a spin.

But the application of rudder has unstalled a wing!!!

I'll get my coat.

[dook]

I'll have to tell the Central Flying School that and tell them they have been wrong since 1912 !!!

[Kemble Pitts]

The physics is correct; I'm not suggesting that this is what you'd want to do to recover from a stall. But you did ask:rolleyes:

[dook]

Sorry old chap, but the physics is totally incorrect.

I must have taught aerodynamics incorrectly for twenty years and so must a retired test pilot friend.

[Kemble Pitts]

OK, justify.

The AoA is the resultant of the descending (vertical) line of the stalled wing and the forward motion (horizontal line) compared to the chord. A boot full of rudder increases the length of the horizontal, thus the AoA reduces. On the other side of the aeroplane the opposite happens, hence the likelihood of a spin the opposite way to the original wing drop.

[dook]

I have no further interest in this.

Goodnight.

[Kemble Pitts]

Fair enough.

[Fl1ingfrog]

Kemble

Even if one accepted that yawing the stalled wing forward reduces its angle of attack, and I'm not convinced, that is not to say that the angle of attack will be reduced sufficiently to unstall the wing. An upgoing wing does not necessarily = an unstalled wing. A perfect spin scenario: stalled, rolling and yawing.

Incidentally, in a climbing turn with a shallow angle of bank and at the stall, with certain types, a sudden and rapid wing drop of the outer wing can happen. Whenever possible I would always demonstrate this.

[Genghis the Engineer]

I'm with Dook and Frog on this.

The upgoing wing may then unstall as the spin develops - that is believed to be the case quite often, but it doesn't stop the spin self sustaining.

G

[Big Pistons Forever]

One exercise I like, which seems to be seldom taught is to link climbing turn stalls with slipping and skidding. I deliberately set up the slip or skid with too much rudder in the desired direction. If the airplane is slipping then the aircraft rolls toward level as it stalls, but if it is skidding it will tuck under inside the turn.

Just saying "skids are bad" doesn't deliver the message half as well as showing people why getting slow and skidding, especially at low altitude is deadly. The overcooked base to final turn with the lots of inside rudder is also a great exercise, however unfortunately some trainers like the C172 are so docile it is hard to do a convincing demo of the skidding base to turn stall. incipient spin

[Kemble Pitts]

This is an interesting debate (and if I offended Dook in some way that was certainly not my intention by the way).

Going somewhat back to the area of the original posting about wing drops at the stall.
It used to be taught, and you can easily go and show it in action, that you should pick up a wing drop at ther stall using rudder rather than aileron (for the purposes of this argument please ignore the multiple pros and cons of either action).

Next time you go flying, and at a suitable height, do some stalling and hope to get a wing drop. Try 'picking the wing up' with a boot full of rudder before unloading the stick. The dropped wing will get picked up - also, as their is ought for nowt as our Northern friends say, the other wing will, likely, then drop instead. We recognise this as spin entry but forget that for the moment also.

So, the wing that dropped first was the one that stalled slightly earlier than the other one - I suggest that the only way its going to stop falling and then come back up is if its 'flying' again, and is now unstalled. I also suggest that that is the result of increasing the wing's forward speed (thus reducing the AoA) as a result of yawing which is the result of the boot full of rudder.

But I am intrigued as to why this is contentious.

[For the avoidance of doubt, this is not the best thing to do to recover from a stall - SSR is release the back pressure, apply full power and then (when the wing is flying again) sort out any roll].

Views please.

[onionabroad]

So, the wing that dropped first was the one that stalled slightly earlier than the other one - I suggest that the only way its going to stop falling and then come back up is if its 'flying' again, and is now unstalled. I also suggest that that is the result of increasing the wing's forward speed (thus reducing the AoA) as a result of yawing which is the result of the boot full of rudder.


Views please.

I imagine the part of this that may be contentious is that by using the rudder to lift the wing, you are not necessarily "unstalling" the wing even if it is having a lower AoA, you are just allowing both wings to stall more evenly.. the lifted wing isn't necessarily "flying" again.

...so ultimately you MAY have made it less dangerous (by some remote margin), but you haven't really fixed the problem

[Kemble Pitts]

Onionabroad

For clarity, I am not suggesting that this is a good or a bad idea, just postulating that this is what happens if you use the rudder.

[onionabroad]

Onionabroad

For clarity, I am not suggesting that this is a good or a bad idea, just postulating that this is what happens if you use the rudder.

oh I know... I'm just speculating on why some may have strong feelings against what you're saying.

[dook]

For those who know little, and there seem to be quite a few, an inverted spin in a Hunter from 40,000 ft would provide an interesting experience !

[Fl1ingfrog]

I've expressed already that I am not convinced yawing the wing will unstall it. However, if you have some faith in this idea you also have to ask the question: to what point in its travels can it be known the wing has been yawed sufficiently? Surely it is not being suggested that the wing can only be unstalled when it is "level" but with what. So, what could be the reference for "levelling the wing". The horizon should take no part in stall recovery.

Pitching to reduce the A of A below the critical angle requires no reference datum. It is sufficient to know that the reduction is achieved by reducing back pressure. This is easily demonstrated.

[Kemble Pitts]

Sorry Dook, but it does seem that you can provide a lot of 'there I was with nothing on the clock but the makers name...' it might be helpful to profer some actual theory to further the discussion.

[foxmoth]

Falling leaf anyone?

[Genghis the Engineer]

I've spun a Hunter inverted. Enter at 30,000ft, 4 turns, recover, pull out from the dive - bottoms at about 15,000ft. Concentrated the mind on height loss - but as it's a swept wing jet massing around 10 tonnes, not all that representative of light GA typically massing about a tonne, with a propeller and a straight wing.

G

[Big Pistons Forever]

I've spun a Hunter inverted. Enter at 30,000ft, 4 turns, recover, pull out from the dive - bottoms at about 15,000ft. Concentrated the mind on height loss - but as it's a swept wing jet massing around 10 tonnes, not all that representative of light GA typically massing about a tonne, with a propeller and a straight wing.

G

As a general observation an inverted spin will not happen in your typical GA trainer. The closest I have come was a botched immelman entry in a C 150 Aerobat. It ran out of steam near the top of the half loop and the student had let quite a bit of yaw develop. I did not say anything because I wanted to see what the student would do when we departed controlled flight. When the airplane stalled it initially flipped over in the start of an inverted spin but then flipped back over to an erect spin which almost immediately developed into a spiral dive. The student sat frozen at the controls doing nothing with a rather humorous gobsmacked expression while all this was happening until I yelled at him," Analyse and Recover !" at which point he did an acceptable spiral dive recovery

The bottom line from my POV. Any discussion of inverted spins have no relevance to the topic of stall/spin in ab initio training

As a general observation I would suggest failing to teach control of yaw and then failing to demand students control yaw in all phases of flight is a weakness in flight training. Unfortunately modern trainers, especially the C 172 will let students get away with feet on the floor flying. One result of this is effective control of yaw when the aircraft stalls and during the subsequent recovery. If yaw is controlled it is impossible for the aircraft to spin so failure to control yaw is not good.......

[Genghis the Engineer]

The bottom line from my POV. Any discussion of inverted spins have no relevance to the topic of stall/spin in ab initio training

Oh I'd discuss it, somewhere around 2-5 minutes on the ground, then get on with something much more immediate and relevant.

G

[justmaybe]

Probably got more out of the foregoing posts than I have on many an FI/FE Seminar(s)!!

[foxmoth]

As a general observation an inverted spin will not happen in your typical GA trainer

maybe not but you then go on to quote the aerobat in a cocked up aerobatic manoeuvre, and many aerobatic aircraft (maybe not so much the aerobat) WILL get into an inverted spin from a botched manoeuvre, the most likely I have found (and how it happened to me) is going for a vertical roll into a stall turn, stick goes forward to keep vertical and you the put rudder in possibly against aileron and off you go.
You then say this should not be discussed in ab initio, unfortunately there are pilots that will try aeros without proper training, these are the ones most likely to mess it up and at least if it is discussed then they have some idea how to recover - also it is not a bad thing if they then go on to aeros to already know the principle, after all it is not that hard to teach - opposite rudder, stick progressively back OR forward until the spin stops! (Obviously just concentrating here on how little change you need to make rather than going through full spin recovery detail)

[Fl1ingfrog]

One of the few good things that have come out of EASA is the introduction of the Aerobatic rating. This at the least reminds pilots that they are not qualified to perform aerobatics until they are properly trained and assessed.

There is only so much you can do within the PPL syllabus before you overload it and possibly put people off flying. When I learnt to fly spinning was mandatory and many left flying because they would not accept the impending spin training or suffered an intolerable reaction to it. The current stalling syllabus is sufficient in its current form when it is completed fully. Sadly this is not always the case. As with some other parts of the syllabus stall training it is not completed, as detailed, but is only carried out sufficient to meet the requirements of the skill test.

[Big Pistons Forever]

Foxmoth

I stand by my contention that the common trainers such as the C 152/C172 or Pa 28 series can’t enter an inverted spin as the significant wing dihedral makes them naturally unstable inverted so that they will transition into an erect spin on their own during the spin entry.

In the case of the C152 aerobat, my experience has been that even in full into yaw aileron and full power would not generate a stable inverted spin

The message for an initio student should not be how to deal with a botched hammerhead, it should be on the importance of reducing AOA to get the wing flying again and control of yaw to prevent a departure from controlled flight

[foxmoth]

BPF, to be honest even a sustained erect spin is difficult to achieve in these aircraft, and I would certainly agree the emphasis should be on reducing AoA to get the aircraft flying, where I would disagree is your statement Any discussion of inverted spins have no relevance to the topic of stall/spin in ab initio training , this certainly should not be discussed with all students as it will confuse, but anyone that has the interest and capability of understanding it should not be blocked from something that will expand their knowledge and understanding of stall/spin.

[rarelyathome]

Fox. Think you have the order wrong there. Unstall the wings first, then full opposite rudder unless the POH says otherwise.

[Genghis the Engineer]

Fox. Think you have the order wrong there. Unstall the wings first, then full opposite rudder unless the POH says otherwise.



Negative.

The "Standard Spin Recovery" used as the start point for flight testing is found in AC23-8 and is opposite rudder, then stick forward. Whilst many aeroplanes may have variations from that, SSR is invariably the baseline.

G

[rarelyathome]

Thanks G - it was late ;) Apologies Fox

[double_barrel]

Forgive a little thread drift. I just chanced upon a video of a float plane crashing on take-off due to a wing drop stall.

https://abcnews.go.com/WNT/video/video-float-plane-crashes-lake-maine-taking-off-65157413

I realize that I have seen several videos showing similar crash on take-off, they seem to result from loss of power on take-off, but then no evidence of any attempt to lower the nose and deal with the issue. That float plane for example seemed to maintain a high AoA until it fell from the sky with one wing down. It looks like he had an entire lake to put it back down on but he didn't. If my interpretation is right, any thoughts on why this happens ? Does the pilot just freeze ? Or is there actually no time/authority to get the nose down at a critical point?

[Big Pistons Forever]

DB

Normal float plane takeoffs have the airplane becoming airborne at minimum flying speed so the drill is to become airborne and then accelerate in ground effect until climb speed is reached and then climb away. Float planes are more vulnerable to clumsy handling right at and after liftoff so you do see more stall accidents in this area compared to land planes. Gusty winds exacerbate the issue and require good skills to manage safely

[Big Pistons Forever]

The "Standard Spin Recovery" used as the start point for flight testing is found in AC23-8 and is opposite rudder, then stick forward. Whilst many aeroplanes may have variations from that, SSR is invariably the baseline.

G

When I am teaching aerobatics we do quite a bit of spinning. One of the things I watch for are students who relax the back pressure prior to first stopping the yaw with the rudder as this can create a very interesting ride :uhoh:

In the ab initio context I demonstrate one spin as a way to show the consequences of not recognizing and avoiding the stall and if the airplane does inadvertently stall; not controlling yaw. The spin recovery is required if the airplane is actually spinning which on all common trainers, requires at least half a turn if not more. Recognition and avoidance of the stall should be the primary focus of ab initio training and instilling the instinctive reaction of froward stick full power and rudder to control yaw at the first sign of the aircraft stalling.

[Genghis the Engineer]

A very experienced test pilot, who became a flying instructor, referred to this in my hearing as "conducting the orchestra" - where pilots, instead of holding the controls firmly and initially in the pro-spin / initial condition, kept moving the stick around, and often didn't keep the rudder on the stop either. As you say, it creates interesting and inconsistent recoveries.

I agree that correct actions in the early incipient stage of the spin are not the same as those from a developed spin. Historically that basically was throttle closed/controls centralised. Interestingly, I explored that during some refresher aerobatic training last year, and the very experienced ex-military aerobatic instructor teaching me insisted that in his opinion whilst that worked consistently, he preferred the UPRT drill of unload in pitch / roll wings parallel with the horizon / pitch to level flight attitude.

So, what else could we do? We went and set up some deliberate gross mishandling upsets, and tried the two different recoveries with identical entries.

The result? Both worked first time every time, but his preferred UPRT approach gave us consistently about half the height loss. I am a convert!

G

[Fl1ingfrog]

Genghis

Please detail the the full recovery from the spin that your instructor was teaching. To my knowledge the EASA UPRT is a course but doesn't specify technique.

[Genghis the Engineer]

The full recovery from the spin was exactly as the POH (in this case for a T67M260), the UPRT - which we also used for an undefined early incipient spin (by undefined I mean from a manoeuver not a standard spin entry, and so with spin direction not yet defined) was as I've said above.

G

[Fl1ingfrog]

I'm still unclear Genghis what it is you are saying. I've attached the T67 Mark 11 spin recovery section albeit this aircraft has the less powerful 150/160 hp engine than the aircraft that you flew. I don't know if the recovery is different.

An issue for understanding for me could be the use of the word "incipient". In aerobatics the term covers the first 3-4 rotations or until the spin stabilizes. In the PPL syllabus the term applies to "wing drop" before rotation begins. There is a very important difference in the recovery technique between these two situations.

[Genghis the Engineer]

Now there's an argument I had with the late, great Darrol Stinton a few times. What is incipient?

Darrol used to reckon it was about the first 6 turns, and instrumented data I've been through from flight tests tends to agree with him - but the convention I am using here is that it is the phase between initial loss of control and the spin mode (e.g. erect to the left) becoming clear to the pilot.

G

[LastStandards]

What is incipient?

Equally, RAF Central Flying School now have quite a nice definition that works with my own students for defining incipient vs full spinning: an incipient spin is one that does not require a full spin recovery technique, while a full spin is one that does not recover using an incipient recovery technique. There is of course the caveat of individual aircraft having their own optimum recovery techniques - cf the farce of the Robin 2160 when first brought into the UK - but as an overall rule it works well. DS of course explored the various modes rather more thoroughly than most of us might in day to day flying, with more understanding of how differing flight path may affect the spin modes!

[Fl1ingfrog]

The robin 2160 gives pretty much the expected 'standard stall recovery' technique within it's POH. An interesting quote directly from it's manual: “Only one action is important – keep the rudder fully in opposite direction!”.

Following an interesting discussion with a number of aerobatic competition pilots I was surprised to hear that recovery from the incipient spin (most common during a short display) was primarily stick forward, I had to try this and found flying the R2160 that indeed by doing this you could recover well onto a very precise and predetermined heading. But what of using such a technique when recovering from a fully developed spin. I also tried this climbing to a safe height. I kept the spin to 6 rotations and then pushed the stick forward: it could have been set in concrete, it was immovable. I then applied maximum opposite rudder and was then, quite quickly, able to recover using the recommended POH spin recovery technique.

The R2160 manual also states that after 3 rotations the engine may stop but, this is not of concern because the engine will recover power quickly following recovery. The CAA did not like this so put in the restriction of a maximum of two turns. The engine stops very rarely but if it It does the POH is proved correct.

[Genghis the Engineer]

When I flew the spin testing on the MXP740 Savannah with a Jabiru 2.2L engine, the engine generally stopped at about 2 turns. It was never considered appropriate to give it a deliberate spinning clearance anyhow, so that was no big deal - but it did show the wisdom of the teaching that you always do such testing over a runway! (Although, as for your Robin, it also restarted easily enough.)

G

[Big Pistons Forever]

Cessna produced a pamphlet in the late 1970’s that expanded on the spin for all Cessna SEP’s by model. For all models the first 180 deg of rotation was considered the spin entry and a normal stall recovery ( ie start with pushing wheel forward) could be used. Only after 2 full turns is the spin considered fully developed and the POH spin recovery method should be used.

The bottom line line for an initio is if you are teaching spinning where you let the spin wind up so that a full spin recovery should be used you are providing negative training as the pro spin controls must be maintained in order to get the aircraft to be established in a spin. The objective of the exercise should be to instil the automatic and instinctive reactions so that the aircraft never gets near to an actual spin mode.

[Fl1ingfrog]

Big Pistons Forever

From your quote of the Cessna pamphlet it makes no sense to me for the following reasons; the PA28-140 Service bulletin 753, Dec 1982 gives a height loss of 1,000 ft for one spin, Cessna 152/172 manuals also give 1,000 ft loss for the first rotation, Robin 2160 suggests 1300 ft should be allowed for a full recovery from the first rotation.

The above figures are given for the published POH spin recovery technique. In most of the light aircraft POH the standard spin recovery carried out for type approval is used although sometimes badly written and vague using terms: "briskly", "pause" etc. The original Slingsby manuals did state that the hand control should be moved forward and centralised but following a number of fatalities this was later amended adding "...even if the stick requires moving fully forward to its limit".

[Genghis the Engineer]

Frog - absolutely nothing you are saying contradicts anything either BPF or I have said. Are you arguing with yourself?

G

[Fl1ingfrog]

I'm not seeking to contradict anyone but put simply searching for good reason to change my view in a debate. Rudeness certainly will not resolve the issue Genghis. You may well keep in mind a quote attributed to Socrates: "the last act of a loser in an argument is to resort to the tool of slander." which of course if true helps no one.

BPF can of course speak for himself but without seeing or at least having a verifiable quote from the Cessna pamphlet i'm not convinced that Cessna have written the words referred to from the pamphlet. I'm absolutely certain though that BPF is genuine in how he remembers the pamphlet and is simply wishing to make a valuable contribution as am I..

[Big Pistons Forever]

The Cessna manual is available at this link

https://mikeklochcfi.files.wordpress.com/2018/03/cessna-spin-manual.pdf

from page 2

Here, in the entry phase, recovery from or prevention of the spin is as simple as normal stall recovery since, in fact, at this point that's all we are really faced with. Coordinated use of rudder and aileron to oppose any tendency to roll should be applied with emphasis on the rudder due to its generally more powerful influence at this point. This should be accompanied by relaxation of elevator back pressure to reduce the angle of attack below that of the stall. Coordinated use of all controls should then be applied to return to normal level flight.

[Kemble Pitts]

An almost textbook spin entry maybe?

[BigEndBob]

No expert on spinning other than normal flying instructor stuff in 152, 172, PA28140 and Tomahawk over 40 years..
But my last Tomahawk spin was exciting, normal entry couple of spins and standard recovery technique..
Then the nose pitched down into a very high rotational mode i had never seen before. But the manual printed that this could occur.
So i waited and waited, getting lower and lower. So at what point do you think this is not coming out.
I had read the Slingsby accident report and conclusions and that came back to me, so i went pro spin, pulled hard back and then recovery mode but more forceful.
And it snapped out of the spin.
I never spun the Tomahawk again, that was some years ago.
I have seen the NASA spin video, but they all seem quite gentle.

[Fl1ingfrog]

BPF

Thank you very much for producing the Cessna Pamphlet which is extremely interesting.

Your said:
"Cessna produced a pamphlet in the late 1970’s that expanded on the spin for all Cessna SEP’s by model. For all models the first 180 deg of rotation was considered the spin entry and a normal stall recovery ( ie start with pushing wheel forward) could be used. Only after 2 full turns is the spin considered fully developed and the POH spin recovery method should be used."

The pamphlet did not say anything of the kind. Below is word for word copied and pasted from the pamphlet:

During this incipient phase, spin recoveries in those airplanes approved for intentional spins are usually rapid, and, in some airplanes, may occur merely by relaxing the pro-spin rudder and elevator deflections. However, positive spin recovery control inputs should be used regardless of the phase of the spin during which recovery is initiated. Briefly, these control inputs should be 1) neutral ailerons and power off, 2) full rudder opposite to the direction of rotation, 3) just after the rudder reaches the stop, elevator briskly forward to break the stall, and 4) as rotation stops, neutralize the controls and recover from the resulting dive. Using these procedures, recoveries are typically accomplished in from 1/8 to 1/2 turn during the incipient phase.

[Big Pistons Forever]

Flying Frog

i miss remembered the exact wording but it would seem clear to me that Cessna is saying that what is in effect a stall recovery will work in the incipient phase (ie up to full 2 rotations). They also state unsurprisingly that a text book spin recovery will also work and is the recommended method after the spin entry phrase (more than 1/2 rotation)

I stand by my contention that spin training, that is deliberately entering a spin in order to effect the recovery using the POH actions, has no place in an initio flight training. All training should be recognition and recovery of the stall, including control of yaw so the airplane never proceeds past the spin entry phase before full control is regained.

Departure from controlled flight that could result in a spin should be demonstrated with realistic scenarios like a full power climbing turn stall ( ie mishandled short field takeoff) or a low power turning descending stall with a boot full of inside rudder ( base to final stall spin)

[djpil]

Just to add an Australian flavour to the discussion after three flat spin accidents in pilot training with three fatalities in recent years. Refer
https://www.flightsafetyaustralia.com/2019/05/spin-deaths-prompt-certification-warning/ following the release of the first accident report. None of the aircraft were approved for intentional spins yet were practicing incipient spins per the PPL training syllabus.

With our new Part 61 licensing regulations, CASA expanded the scope of stall training for PPLs requiring incipient spins in a variety of scenarios yet omitted to define what was actually required in their so-called Manual of Standards.

I note that the people who write AFMs would use this definition of a spin from AC 23-8C: "A spin is a sustained autorotation at angles-of-attack above stall. ....". The manufacturer of the aircraft in that first accident report confirmed that intentional incipient spin entries are not permitted.

We are still waiting for further advice from CASA and I eagerly await the next two accident reports as I anticipate other issues.

[Fl1ingfrog]

djpil

I agree with you completely and it is a concern that there is not a recognised definition of an incipient spin. Our own debate illustrates the point. BPF, the Cessna pamphlet in no way supports the idea that a stall recovery technique should be used for an incipient spin recovery ".....merely by relaxing the pro-spin rudder and elevator deflections," indeed it warns against it: "...... positive spin recovery control inputs should be used regardless of the phase of the spin during which recovery is initiated". We know that some types are very difficult to spin and just as hard to maintain in a spin such as the C172 and, only by way of explanation the pamphlet acknowledges this but goes no further. It must always be remembered and continuously emphasised to the student, it seems many instructors as well, that a well balanced aeroplane within its "utility" limits may be a very different beast than when it is operated outside these limits closer to it's maximum all up weight and aft centre of gravity.

[markkal]

Incipient spin training, like every training while maneuvering on the back side of the power curve involves skills, reflexes, techniques, knowledge and awareness that can only be instilled through specialised adavanced training requiring the full investment of the instructor. This in terms of proficiency and achieving consistency thereafter. It takes time, money and dedication .


There are schools and instructors out there, not many of them, which are qualified for the task. Its not enough to be good, one must master the realm of slow flight and spin. It is too dangerous in terms of risks and implications. Master it to the point that it will be difficult to make a mistake. This is the "cost " of better safety.


Slow flight up to the full spin is a flight regime with its own rules and techniques; which are often counterintuitive It takes specialised assistance and hours of personal rehearsal after reaching consistency, as it is a perishable skill, it has to be kept "current" .


The debate will be sterile and never ending, just go out there, learn, practice, the endless debate will be resolved showing the maneuver and its recovery ONCE in full confidence, period.

It will look "easy", which it is not, but became "easy" after hours and hours of correct practice.. Like eveything in aviation and also in life, there are no short cuts to profesionalism. You have to give it the time and your full investment.

[Genghis the Engineer]

No expert on spinning other than normal flying instructor stuff in 152, 172, PA28140 and Tomahawk over 40 years..
But my last Tomahawk spin was exciting, normal entry couple of spins and standard recovery technique..
Then the nose pitched down into a very high rotational mode i had never seen before. But the manual printed that this could occur.
So i waited and waited, getting lower and lower. So at what point do you think this is not coming out.
I had read the Slingsby accident report and conclusions and that came back to me, so i went pro spin, pulled hard back and then recovery mode but more forceful.
And it snapped out of the spin.
I never spun the Tomahawk again, that was some years ago.

And that, dear readers, demonstrates why I think that people who spin without a parachute or other "get out of gaol card" are extremely foolish and I endeavour never to do so myself.

G

[Big Pistons Forever]

What Genghis said :ok:

Deliberately entering a spin and not recovering immediately ( ie within 1/2 turn or ideally less) is an aerobatic maneuver and should be taught as an essential part of an introduction to aerobatics in an aerobatic aircraft (or glider) under the guidance of a aerobatic instructor, not in a non aerobatic airplane with an instructor with no aerobatic training or experience

More than 25 years ago the FAA eliminated spinning from the PPL syllabus in favor of enhanced stall recognition and recovery training. Since then the fatal accident rate for stall spin accidents has actually gone down.

[TheOddOne]

The same happened in the UK, I'm pleased to say. Ab initio spin training was killing instructors.

I had to demonstrate spin recovery for my initial issue Instructor rating. Since then, during a revalidation, I have had demonstrated to me aileron reversal from a turning full-power stall in a C152. The examiner very carefully turned to the left. At about 30 deg AOB and a silly pitch attitude, the right wing gave up lifting and we snapped pretty quickly to the right - 'you have control - recover'. Actually, it entered a spiral dive to the right as balance had been maintained throughout so recovery was pretty easy even though the aircraft had dramatically changed both pitch and roll attitude. I think the examiner had practiced this a lot to get it to go just right. I'm pleased the examiner saw fit to show me things that are outside the strict syllabus with a detailed de-brief of how not to let the student get you there. We have the option to attend a 2-day seminar every other revalidation. I've been to one and won't again. I get far more value from a day with an examiner, even though it takes me outside my comfort zone (and is more expensive).

Where is the value in a seminar, anyone?

TOO

[BigEndBob]

Well every instructor renewal i have done in the UK involves spinning, if we take the C152 up.
Also done on instructor courses.
Getting harder to find suitable aircraft.
And they are all getting older.
Have been one or two accidents spinning certain types, but can't say it was epidemic to stop doing in benign aircraft. If anything if a few demos scares the student, good, don't stall!
And the seminars have been a waste of time, we might as well just purchase the notes they give us and save us the hassle of losing two days pay.
A better system would be a list of recommended videos to watch and learn.
I think the US has done that, with credits through a AOPA scheme.

TheOddOne, The turn with the flick out seemed a favorite of a certain Mr P S, often done in types not approved for spinning. Few spin accidents aren't actual spins, just wing drops, incipient, to very steep spiral dives, still requiring lots of height to recover.

[Dan Winterland]

My 2d worth from what I learnt at CFS in the early 90s. The definition of a full spin (CFS) is 'when the aerodynamic and inertial forces have reached a state of equilibrium'. I like this, if you sit and think about it, it makes sense. Identification of a spin is (CFS again) 'buffet with un-demanded roll'. But how do you know your incipient spin has progressed to a full spin? with some aircraft, it's obvious. With others, not quite so. About half way through my RAF instructing career, the spinning syllabus changes with recoveries from the incipient stage being practiced before full recoveries. The incipient recovery for most types is centralise the controls, close the throttle, recover from the ensuing unusual attitude. Essentially, the current UPRT recovery. If this doesn't work, you are in a full spin and the correct spin recovery for that aircraft type should be applied.