How safe is stall practice in a non spin certified aircraft?

[vabsie]

Sorry if this has been covered before ..

As you know, we practice a fair amount of stall recovery as part of PPL training.

My question is this:

In a recent flight lesson in a Robin 2120 practising stalls, my instructor made a comment along the lines of: Lets always make sure we recover from a potential stall early so that we don't end up spinning, as we might not get out of it.

Maybe the comment was a bit of tongue and cheek (although I appreciate the seriousness of recognising a potential stall early) - It did make me wonder however, if the aeroplane was really to enter a spin (accidentally) for whatever reason - is it almost a done deal that we would not have gotten out of it as this particular aircraft is not spin certified?

I appreciate that there is a difference between a fully developed spin and an incipient spin - I guess I'm referring to a fully developed spin.

Keen to hear your thought?

Vabsie

[Pilot DAR]

In a type certified aircraft, it will be very safe to enter and recover a fully developed stall (with all of the appropriate precautions, of course), without spinning. If a spin were to develope because of your carelessness, or poor technique, the aircraft would be recoverable with proper technique and adequate altitude.

You are flying an aircraft which meets this, or something like it (my bold):

523.201 Wings Level Stall

(a) [ It must be possible to produce and to correct roll by unreversed use of the rolling control and to produce and to correct yaw by unreversed use of the directional control, up to the time the aeroplane stalls.
(b) [ The wings level stall characteristics must be demonstrated in flight as follows. Starting from a speed at least 10 knots above the stall speed, the elevator control must be pulled back so that the rate of speed reduction will not exceed one knot per second until a stall is produced, as shown by either:
[(1) An uncontrollable downward pitching motion of the aeroplane;
[(2) A downward pitching motion of the aeroplane that results from the activation of a stall avoidance device (for example, stick pusher); or
[(3) The control reaching the stop.
(c) [ Normal use of elevator control for recovery is allowed after the downward pitching motion of paragraphs (b)(1) (http://www.tc.gc.ca/aviation/regserv/carac/CARS/cars/523/english/523sa-be.htm#523_201_b_1) or (b)(2) (http://www.tc.gc.ca/aviation/regserv/carac/CARS/cars/523/english/523sa-be.htm#523_181_b_2) of this section has unmistakably been produced, or after the control has been held against the stop for not less than the longer of two seconds or the time employed in the minimum steady slight speed determination of 523.49 (http://www.tc.gc.ca/aviation/regserv/carac/CARS/cars/523/english/523sa-be.htm#523_49).
(d) [ During the entry into and the recovery from the manoeuvre, it must be possible to prevent more than 15 degrees of roll or yaw by the normal use of controls.
(e) [ Compliance with the requirements of this section must be shown under the following conditions:
[(1) Wing flaps. Retracted, fully extended, and each intermediate normal operating position.
[(2) Landing gear. Retracted and extended.
[(3) Cowl flaps. Appropriate to configuration.
[(4) Power:
[(i) Power off; and
[(ii) 75 percent of maximum continuous power. However, if the power-to-weight ratio at 75 percent of maximum continuous power result in extreme nose-up attitudes, the test may be carried out with the power required for level flight in the landing configuration at maximum landing weight and a speed of 1.4 VSO, except that the power may not be less than 50 percent of maximum continuous power.
[(5) Trim. The aeroplane trimmed at a speed as near 1.5 VS1 as practicable.
[(6) Propeller. Full increase r.p.m.. position for the power off condition.]
(Change 523-4 (96-09-01))
(Change 523-5)
523.203 [Turning Flight and Accelerated Turning Stalls

[Turning flight and accelerated turning stalls must be demonstrated in tests as follows:
(a) [ Establish and maintain a co-ordinated turn in a 30 degree bank. Reduce speed by steadily and progressively tightening the turn with the elevator until the aeroplane is stalled, as defined in 523.201(b) (http://www.tc.gc.ca/aviation/regserv/carac/CARS/cars/523/english/523sa-be.htm#523_201_b). The rate of speed reduction must be constant, and:
(1) [ For a turning flight stall, may not exceed one knot per second; and
(2) [ For an accelerated turning stall, be 3 to 5 knots per second with steadily increasing normal acceleration.
(b) [ After the aeroplane has stalled, as defined in 523.201(b) (http://www.tc.gc.ca/aviation/regserv/carac/CARS/cars/523/english/523sa-be.htm#523_201_b), it must be possible to regain wings level flight by normal use of the flight controls, but without increasing power and without:]
(1) Excessive loss of altitude;
(2) Undue pitch-up;
(3) Uncontrollable tendency to spin;
(4) [ Exceeding a bank angle of 60 degrees in the original direction of the turn or 30 degrees in the opposite direction in the case of turning flight stalls;
(5) [ Exceeding a bank angle of 90 degrees in the original direction of the turn or 60 degrees in the opposite direction in the case of accelerated turning stalls; and
[(6) Exceeding the maximum permissible speed or allowable limit load factor.
(c) [ Compliance with the requirements of this section must be shown under the following conditions:
(1) [ Wing flaps: Retracted, fully extended, and each intermediate normal operating position;]
(2) Landing Gear: Retracted and extended;
(3) Cowl Flaps: Appropriate to configuration;
(4) [ Power:
[(i) Power off; and
[(ii) 75 percent of maximum continuous power. However, if the power-to-weight ratio at 75 percent of maximum continuous power results in extreme nose-up attitudes, the test may be carried out with the power required for level flight in the landing configuration at maximum landing weight and a speed of 1.4 VSO, except that the power may not be less than 50 percent of maximum continuous power.]
(5) Trim: The aeroplane trimmed at a speed as near l.5 VS1 as practicable.
[(6) Propeller. Full increase r.p.m. position for the power off condition.]
(Change 523-4 (96-09-01))
(Change 523-5)

Always ensure you are properly trained and current in stalls, and if possible spins, before you fly these alone, or fly with appropriate supervision.

That said, a lot of flight testing goes into assuring that the certified planes you fly are safe and tolerant.

[N707ZS]

In a recent flight lesson in a Robin 2120 practising stalls, my instructor made a comment along the lines of: Lets always make sure we recover from a potential stall early so that we don't end up spinning, as we might not get out of it.



Why didn't you ask your instructor about his comment after the flight?

[john_tullamarine]

and recover a fully developed stall

I'd add a caveat -

(a) the certification stall technique has varied over the years

(b) it is important to review the certification basis of the particular aircraft to determine just what was what

(c) the typical pilot training stall technique can vary somewhat from what the particular Type/Model may have demonstrated

(d) in particular, for some aircraft, holding the initial stall for an extended period may produce unexpected results. One tale I have heard from a very experienced TP related to a well-known twin which, when held into the developing stall ... promptly flicked into an inverted spin. The student TP who caused the problem no doubt learned a useful lesson regarding cavalier and ad hoc flying techniques ..

(e) it is a good idea to read what the OEM has to say on stall technique and not casually go too far away from that guidance .. unless you really do know what you are doing.

[vabsie]

N707ZS - When he said it I took it just as that: "That it would be very risky to let the aircraft spin"

I obviously thought enough about it subsequently to want to post a question on pprune.

Thanks

Vabsie

[Final 3 Greens]

Vabsie

I think, from your comments, that you may be a student pilot. I have checked your profile, but is does not say. If my assumption is wrong, please accept my apologies.

I'm a PPL with a few hundred hours experience, which is rather less than some posters around here.

But I think it is enough to offer one interpretation of your instructors comments.

For most of us PPLs, the most likely scenario for a stall/spin/die accident is turning final.

If we are alert to the risks and symptoms of a stall and avoid these, then we won't spin.

If we spin at 500 feet, then recovery is very unlikely in most types.

That's my take on the comment, not that spinning is irrecoverable at altitude.

Why don't you ask the instructor? If I'm right, then kudos to him/her for trying to keep you safe with a very practical message, which has got through :ok:

[Pace]

Does your instructor get you to recover from an incipient takeoff too :ugh:
Explain to him that you would like to experience fully developed stalls in all configurations including the most likely landing config in a banked turn.
I don't know where you are in your training regime but you need to be fully comfortable with anything the aircraft can throw at you and iIMO that should include spins.
At some point go and get some aerobatic lessons as it will help your confidence no end and that includes experiencing spins

Pace

[Fuji Abound]

I am guessing that you have yet to experience a spin?

Your first spin hopefully given that it is planned will still come as a big surprise. It is probably like nothing you have experienced before. Personally I think even if you had been taught the theory some pilots encountering an unexpected spin would not recover however much height they had. With some training your chances would improve enormously to the point at which the aircraft would become a greater factor than the pilot. That is because while the earlier post is correct about certification aircraft do vary in their readiness to recover from spin particularly if the spin is fully developed. Moreover aircraft vary greatly as to how they spin and how disorientating the spin is.

Pace is correct, I think everyone is well advised to experience spinning with an instructor if they are serious about their flying even if they never revisit spinning again. Just experiencing a few spins makes it so much less of a shock should it ever happen in anger.

To return to the earlier post and to be slightly pedantic not all seps have achieved the same degree of certification, for example a cirrus may well not recover from a spin; the poh requires the pilot to activate the chute should a spin develop.

[Final 3 Greens]

Pace/Fuji

Without knowing Vabsie's level of experience, I think it is hard to reach a firm judgment. Context is pretty relevant in this case.

It sounds to me like the advice an FI would give to a pre-solo student.

If you bear in mind the solo student accident at Southend a few years ago, this advice makes complete sense to me in the context of early training.

Vabsie, are you prepared to share your level of experience?

[BackPacker]

I'm working on the same assumption. Pre-PPL, possibly pre-solo student.

I agree with what's been said. Get your instructor to demonstrate you a fully developed spin. The Robin 2120 is one of the few training aircraft that's cleared for intentional spins (well, at least the R2160 is, so I would assume the 2120 is too - but check the POH to make sure!). It's a great experience and one that can take the fear out of stalling. Whether that's a good point or not, I don't know though.

But I'd like to add another important point:

As you know, we practice a fair amount of stall recovery
[...]
In a recent flight lesson in a Robin 2120 practising stalls,

At your stage of training you are not practicing stalls. You are practicing incipient stall recognition and recovery. Your instructor demonstrates that, and ingrains that in you by doing full stalls, but being able to do full stalls is NOT the objective here. Being able to recognise the signs of a stall, and to do something about it is.

A full stall is a flight situation that you have to avoid at all costs, and at all altitudes, unless you are a test pilot or an aerobatics pilot (with the appropriate training, and in an appropriate aircraft). Because stalls can be dangerous even if they don't turn into a spin. Yes, your basic single engine straight wing trainer will probably have docile stall characteristics but there's no guarantee that the aircraft you will fly in the future will behave the same. Especially if they have multiple, underslung jet engines, swept wings, T-tails and whatnot. (*)

So what you should focus on is to recognise the signs of an impending stall (sloppy controls, stall warner, buffetting are the usual three, and in a S&L 1G stall you can also add low power and high pitch) and learn the correct recovery technique. Especially once you get to the solo stage. If you keep this in mind, and keep the ball in the middle during any stall recognition practice, you should not need to worry about spinning.

(*) Notice point (b)(2) in Pilot DARs post. Aircraft with a stick pusher don't have to get into a full stall in order to certify. They just have to be recoverable from the point where the stick pusher activates. And that may be several degrees AoA short of the point where the aerodynamic stall happens. Because in those types a stall will, in all likelihood, be unrecoverable within a reasonable height or without overstressing the aircraft.

[Morrisman1]

well, at least the R2160 is, so I would assume the 2120 is too - but check the POH to make sure!

The r2160 has an extra directional stabiliser under the rudder to assist in spin recovery. I cannot remember what its called sorry.

[Pace]

Backpacker

I totally agree that avoiding a stall and knowing the signs is vitally important. That doesnt matter whether the pilot is a student or multi thousand hour.

But sadly there are situations where a full stall will occur maybe because the pilot is distracted or whatever or even a spin.

For me as an ex racing driver its a bit like teaching someone to drive, explaining about understeer or oversteer and teaching drivers to avoid those situations.
One day they wont! The driver who is totally comfortable out of shape and can play the car in understeer or oversteer situations is far more likely to avoid a crash than the avoid trained driver.

While it is vitally important to teach avoidance and recognition for me its also vitally important that our pilots know most things that the aircraft can throw at them and be comfortable with that.

Maybe I am old school and have had examiners who are old school too but we even fully stall twins at 10K in all configs as well as jets.

If it was up to me I would build a couple of hour aerobatic training into the PPL and drop a couple of hours off something less important.

Pace

[Mark1234]

The r2160 has an extra directional stabiliser under the rudder to assist in spin recovery. I cannot remember what its called sorry.

Ugly is the word you're looking for! and the strake/keel bit makes it the only nosewheel aircraft I've ever 3 pointed :O

It also gives some clues about the spin characteristics.

For Vabsie, I suggest it's harder to get into a spin than you think, though that's no reason to be complacent, and for most types (there are sure to be exceptions), a swift removal of AOA (remove back stick) will stop any wing drop etc. progressing.

[Flyingmac]

Have a look under Refresher Training.
http://www.caa.co.uk/docs/33/20110217SSL01.pdf

[BackPacker]

and the strake/keel bit makes it the only nosewheel aircraft I've ever 3 pointed

Me too. Typically during flapless landings. Not something I do voluntarily but the instructors insist during a clubcheck. Their aircraft, their rules is what I tell them. Only a "positive" landing will prevent a tailstrike. Just.

We recently had to replace that tailskid-thingy because it was too worn through to be safe.:eek:

I've been Googling and indeed the R2120 doesn't seem to have that keel. So I would assume its spin characteristics to be different indeed, assuming that spinning is allowed in the first place. So, yes, check the POH for your specific aircraft to see what it has to say about it.

If it was up to me I would build a couple of hour aerobatic training into the PPL and drop a couple of hours off something less important.

Agree. Although I can't think of anything right now that I'd like to leave out of the PPL syllabus. Come to think of it, the stuff that's covered in there is pretty minimal anyway and there are things I'd like to see added instead of removed (proper GPS usage, glass cockpit awareness, advanced engine management including injection, diesel, FADEC to name a few).

Anyway, the story I've heard is that more pilots (both students and instructors) were killed during spin training than during actual stall/spin accidents. That's apparently why the authorities took it out of the syllabus. Plus, at the same time, a far better understanding of the aerodynamics of a spin, how to design an airframe to be less spin-prone, and the development of certification standards like the ones Pilot DAR mentioned.

[vabsie]

Hi All ..

Thanks for all the valuable comments so far.

I have done around 27 hours of flight training and did my solo after 12/13 hours at Stapleford in the UK.

The reason I have revisited stalls, and general handling recently was because I moved from the UK to New Zealand and haven't flown for about a year before my first lesson in New Zealand - And the new club of course wanted to confirm my ability.

My new instructor was pleased with my stall recovery technique. In the UK I have done one incipient spin, which was not a great feeling, but I managed.

The main reason for me asking the question was because I now train in a different aircraft, a Robin R2120 as suppose to a Cessna 152 which was my primary training aeroplane in the UK, and the instructor's comment about having to be very careful about not spinning. I remember in the UK my instructor used to say that it would not be the end of the world should we enter a fully developed spin before practising the incipient spin. I guess he wanted to reassure me.

I therefore assumed that maybe with certain aircraft it is impossible to exit a fully developed spin, even at altitude, and considering my instructor's comment wasn't sure whether the Robin R2120 was perhaps such an aircraft.

I hope this explains my situation a little better - hope it's not a silly question.

Thanks

Vabsie.

[FlyingStone]

I think that every certified single-engine aircraft (at least according to EASA CS-23 and CS-VLA) must be able to recover from one-turn spin or a three-second spin, whichever it takes longer plus there are several requirements that spin characteristics shouldn't require above an average handling abilities, ... Everyone interested in details can read about the requirements in CS-23.221 CS-VLA 221. Provided this isn't satisfied, the aircraft has to be redesigned or fitted with balistic recovery system (Cirrus for example). So basically, every certified aircraft (except few aircraft which have BRS fitted insted) are able to recover from a single-turn spin, which would be result of a poorly executed stall.

As said before by Fuji and others, you should get a proper aircraft and an instructor, who is comfortable doing spins (many aren't) and try a few spins. I'm sure the first spin entry and recovery will probably be demonstrated by an instructor, and you will fell somewhat confused during the entry, since you aren't used to that kind of unusual attitudes and you most likely haven't done much handling at speeds which aircraft achieves during the recovery.

I agree with Pace, spin training should be included in PPL training. But don't get me wrong, I'm not saying one should be proficient in spin in order to show off in front of his buddies, girls, etc, but to be able to recognize and recover from one of the most deadliest types of accidents in GA: stall/spin on takeoff. Since most of the described accidents happen on takeoff/landing and I believe there is no way one could make proper recovery from a spin at 1000ft AGL, if he/she never done it before (reading on the subject helps, but there is no real substitute for actual flight training - otherwise the requirements for obtaining PPL would be: read 10.000 pages about flying and do the skill test), much less at 200-300ft where the stall/spin usually happens.

I see two main problems in spin training. First one is the lack of instructors, being able or comfortable to show proper spin entry and recovery, since most of them did the minimum spin training required for the issue of FI rating and off they went, probably not doing another spin ever again. The second issue is probably more serious: more and more new two-seat primary trainers are certified according to CS-VLA, which doesn't allow intentional spins (regardless of any flight testing that was done on that matter), unless you get an exception from EASA (which I believe takes a long time and a lot of money).

[Pace]

Backpacker

A spiral dive is a far more violent maneuver
Than the Spin.
My concern is the amount of students who can confuse the two with disastrous consequences.
You cannot teach that natural identification in the class. Being familiar and confident with both is a far more reliable avoidance.
I take your point that more pilots were killed practicing spins than for real.
The answer to that is to be more selective on aircraft that can be used for spin training or to add the two hours aerobatic training into the PPL syllabus in proper aerobatic machines.
As I have stated before train our pilots to be pilots not aircraft drivers

Pace

[vabsie]

The other thing that crossed my mind was whether I should perhaps switch back to training in a Cessna 152. I have done most training in a 152 and only 3 hours or so in the Robin 2120.

I do enjoy training in the Robin as it's much newer than the club's cessna 152, however, my understanding is that the Robin R2120 is not that common (I don't see many, or any other flying clubs use them), and I can therefore only assume that it would be difficult to compare it's actual safety record with that of a cessna 152 - I guess newer does not always mean better?

It also doesn't help that I just found this when doing a bit more research on the type of aircraft I train in - It is actually one of my club's aircraft - I appreciate you need to understand the circumstances in order make a more informed judgement.
Crash survivor praised - timaru-herald | Stuff.co.nz (http://www.stuff.co.nz/timaru-herald/45504)

Cheers for reading / all the advice and pointers

Vabsie

[Jan Olieslagers]

Don't know if it is very relevant, but here goes anyway:
In my country, and probably in many, it is forbidden to perform spins in a microlight. Yet stall and stall recovery are among the exam tests so they do get practised by every Belgian microlight pilot. I suppose the same must apply to many other countries.

[BackPacker]

Vabsie, crashes of light aircraft are very rare and the few statistics that might be gleaned from them will not tell you all that much about the safety of a particular airframe. So just because you happened to stumble upon a story about an R2120 crash doesn't mean they're less safe than a C152.

in fact, once you start reading accident reports a bit more you will quickly realize that the biggest cause of light aircraft crashes is actually pilot error. Continued flight into IMC, fuel exhaustion or fuel starvation, flight outside the structural limits of the aircraft or gross mishandling of the aircraft at low level. Not by engine or airframe failures.

Personally I like the R2160 a lot more than the C152. It feels much roomier with a much better view. And of course the one I fly has the ability to be turned upside down... :E

But anyway, you need to realise that at your stage of training it's best to stick to one airframe. Whether that's a C152 or an R2120 doesn't really matter. They're both perfectly good trainers. Once you've got your PPL and a few hours experience, you will want to get checked out on several (maybe all) types that the club operates. This gives you the ability to pick the aircraft type that's best for the mission that you're going to fly.

So pick an aircraft type that you find comfortable to fly in and that has good availability. Finish your training on that type. Other types will come in due course.

[Morrisman1]

If I remember correctly, that r2120 that crashed was the result of the pilot trying to out climb rising terrain.

I wouldnt say the robin is any more or less safe than anything else out there, the r2160 has pretty good performance (best i have had is 1700fpm on a high pressure winter morning with only me and 2 hours fuel) and visibility is excellent which is definitely a good safety feature.

Just gotta remember the plane is only as safe as the pilot flying it

[Genghis the Engineer]

I have lots of thoughts on this thread, and quite a few disagreements with some of the previous posters.

Firstly - a stall in itself, in a certified aeroplane, is NOT dangerous. At a safe height it is a perfectly reasonable thing to practice, and I believe that as well as stall avoidance and slow flight, all pilots should practice a proper stall once in a while. Very few certified aeroplanes will show any tendency to spin from a sensibly conducted stall, and pretty much all of those will recover from the incipient spin if you simply put all of the controls in the middle and close/keep closed the throttle.

What will kill you is not the stall and stall recovery, it is the height loss if you stall close to the ground. For this reason, it is generally sensible not to practice stalls anywhere below 1500ft agl, or 3,000ft agl if being particularly cautious for any reason. It is however sensible to practice stalls in the circuit - by which I mean visualise an imaginary runway at, say, 3,000ft and practice approaching the stall and recovering from the finals turn, approach, go-around, and climb-out (the last two being statistically the most dangerous, not the finals turn - although that certainly is significant).

A sharp pilot, practicing a stall and recovery deliberately is likely to lose 50-100ft in the recovery, whilst an average pilot recovering from an inadvertent stall will probably lose 200-300ft. Given that, and a bit of safety margin, it's below 500ft that stalls are truly dangerous.


When we certify a new aeroplane type, we will look at a range of stall scenarios - flap settings, power, bank angle, deceleration rates - going rather beyond what should be flown during PPL training. If the aeroplane shows any tendency to spin, that must be sorted out before the aeroplane is certified.

When we certify a non-aerobatic aeroplane type, we still spin it, still confirm that it will recover within a turn, still evaluate mishandled recoveries, and still confirm that it has no unrecoverable spin mode. What we don't do is go beyond 2 turns - rather more is required for an aerobatic aeroplane.

In the UK for the last 12 years, this has also applied to microlight aeroplanes - although that is not the practice in most countries. However, the large powerful cruciform tails on most microlights together with existing requirements for good low speed handling, tend to assure very good stalling characteristics anyhow. The best spin recovery for most microlights however is to close the throttle and put the stick and rudder in the middle - NOT the conventional light aeroplane opposite rudder recovery (there are numerous reports and research papers out there proving this, it's not just my opinion, although I did write some of the reports.)


So, in my opinion, whilst the first and most important part of stall training is avoidance, this is certainly followed by recovery. Practicing stalling is essential for a safe pilot, and at a reasonable height, is a perfectly safe and sensible thing to do. The risk of a spin is tiny, and of an unrecoverable spin far tinier still.




Further thoughts: train now on the nearest possible aeroplane to what you plan on flying after you have your licence. There's nothing wrong with either the C152 or the Robin, nor particularly with switching types in the middle of training - just don't switch too often until you're rather more experienced (and licenced). Personally I'd stick with the Robin, but purely because I think that they're more enjoyable to fly.

G

[Pilot DAR]

Ideally, good initial training will focus first, but by no means only, on stall and spin avoidance. With good pilot skill (though still in the training phase) stall recovery should be instinctive. A stall which threatens flight safety is going to happen when you're trying to do/not do something else in flight, and you're distracted. Recovery must be instinctive. Also, remind yourself, that it is perfectly acceptable for a well controlled stall to go unrecovered on every flight - the flare and touchdown.

It is possible in any light type (certainly some more easily than others) to aggravate a simple stall into something which turns into a spin. This is why you'll be taught to recognize and recover a stall promptly, but effectively, the first time. A buggered up stall recovery is taking you much closer to a spin.

The spin in a certified light aircraft, in and of itself, is not a serious problem, as long as you are going to correctly recover it, with lots of space around you, and without exceeding limitations. Do not go spinning without proper training and supervision, but certainly do go spinning. I am not an expert on spinning, as it is a very complex subject. But, I have spun about a dozen aircraft types during certification flight testing, and have experienced very different characterisitcs, and recovery conditions.

(Nearly) all ('cause I know nothing about Cirrus) certified aircraft are recoverable from a spin, it's a design requirement. Those which are not spin approved are so either because the manufacturer did not wish to have spin approval, or more commonly, because though recoverable, you get very close to limitations doing it. Add to that, that the recovery technique may be variable, based on configuration, and the techniques or cautions too variable to try to describe to the pilot in the flight manual.

My recent testing experience (on test flight permits) includes many stalls in two Piper Navajos, where, while trying to accomplish minimum altitude loss, it was easy to get a secondary stall, and have a rather messy secondary recovery. Certainly a spin could have been obtained doing that, if one was careless. In January, I did more than a dozen spins in a modified Cessna Grand Caravan. Though the handling of this larger aircraft in the spin is magnificent, it would be easy to exceed limitations during the recovery, without great caution. I installed a G meter, and was happy I did, as the recovery for a forward C of G gross weight spin required a 2.8G pull, at Vne. There's not much room to get that recovery wrong! The aft C of G handling and recovery, though also fine, was very different.

There's a video clip here: YouTube - C208 spin clip.m4v

[They're both the same video, I don't know why it's there twice]

As for your instructor making a remark about it being risky to spin the aircraft, perhaps your instructor is more referring to his/her comfort level, rather than the capability of the aircraft. Ask how experienced you instructor is spinning this type.

[Fuji Abound]

Is that video a spin - looks barely developed to me.
;)

[Pilot DAR]

One turn in, one turn out, that's all I am required to do. At forward C of G, I could not have held it in any more than that, it was on it's way out, no matter what I did. Observed peak rate of descent later calculated to be 9200 FPM.

At aft C of G, it would have stayed in much longer, I had to actually recover it out.

[Jan Olieslagers]

Genghis, can I interpret your words to mean that, if my beautiful new bird has been certified in the UK, it has been tested to resist and survive a certain degree of spinning? Not that I am wanting to try it out, my stomach is rather delicate, and surely I'd not even think of trying it without proper training - but it would be nice to know, for added reassurance.

[VOD80]

PilotDAR, fabulous video. It must be something else to spin something so big!

[ProfChrisReed]

It's likely that intentional spins are prohibited - if you find yourself spinning you are still permitted to recover the aircraft.

A number of long-winged gliders are not certified for intentional spinning, but have all been tested in certification and shown to recover. These gliders are likely to exceed vne during the recovery or suffer some structural damage, so won't be re-usable, but you should survive.

[Genghis the Engineer]

Genghis, can I interpret your words to mean that, if my beautiful new bird has been certified in the UK, it has been tested to resist and survive a certain degree of spinning? Not that I am wanting to try it out, my stomach is rather delicate, and surely I'd not even think of trying it without proper training - but it would be nice to know, for added reassurance.

That's correct, although do check that you have the same build and modification standard as we do, and we only started spin testing in 1999 - anything certified before then probably hasn't been spin tested.

The approved lists are to be found on the BMAA and LAA websites (look for documents called "TADS" and "HADS".

I'm a little out of touch, but I don't *think* that your Apollo Fox has ever been approved in the UK.


If you want a stalling or spinning assessment doing, I'm open to offers, or I'm sure that Pilot_DAR would enjoy a holiday in Belgium. It's a necessarily slightly slow process however.

G

[Blink182]

Very apt this thread.......... We had a situation within our group just the other day with our vintage taildragger (Intentional spins prohibited). The aircraft was on a Permit test flight and the pilot flying the test schedule managed to put the aircraft into a spin whilst carrying out the stall test..........As the aircraft stalled it dropped a wing ( usual behaviour in this aircraft....it rarely stalls straight ahead) and this "ace" only tries to use aileron input to pick up the dropping wing....... result is that aircraft immediately drops away and rotates quickly..........luckily the pax/observer ( another group member with a lot more experience and awareness) quickly intervenes and applies corrective rudder and gets the stick central for a standard recovery....which takes a lot more height than would have been ......Ace seems suitably chastened and hopefully has learnt a valuable lesson...........If this had happened at a lower altitude and unexpectedly , then I think that we would all have be reading about a smoking hole:mad:

[Pilot DAR]

stick central for a standard recovery

Well.... it sounds that the corrective control inputs were appropriate in this case, and credit to the mentor pilot for keeping things safe...

However, the use of ailerons, in correct harmony with the other flight controls, for a spin recovery, is entirely correct. There are some instructors who teach that ailerons are not to be used during spin recoveries. Generally, this is not correct.

Though the wording of the standard has varied over time, the most recent reads:

[ It must be impossible to obtain unrecoverable spins with any use of the flight or engine power controls either at the entry into or during the spin;

A manufacturer may specify a recommended spin recovery procedure, and that may be the one which has shown to result in the quickest recovery, but the "normal" (co-ordinated) use of controls, which certainly would include the use of ailerons, must also work. The only example I can find of a recommendation to NOT use ailerons during a spin recovery, is the Cessna Caravan, where an up going aileron also sends up a roll spoiler. But, I'm sure that it would still recover either way.

I am in the third day of flight test technique training, and this was a highlighted issue today, from the very experienced (ETPS Grad) test pilot. The flight controls are to be used "normally" for a spin recovery. "Rudder only" can be dangerous. You've just departed controlled flight because you have attempted yawed or cross controlled flight, now you're going to completly yaw the aircraft in the other direction in an attempt to regain control. It does not sound as good as the co-ordinated use of all controls as they are designed, approved, and intended, to regain control.

I have challenged instructors to show where the use of ailerons is prohibited in spin training techniques, and no instructor ever has, other than to say "that's the way I was taught"....

Take spin training, which should include the appropriate, co-ordinated use of ailerons during recovery.

[BackPacker]

Take spin training, which should include the appropriate, co-ordinated use of ailerons during recovery.

Although I agree with the theory that you present, I don't agree with this blanket advice. For someone without a lot of experience in aerobatics or test flying (as the OP on this thread) I would say: Take spin training but not before you have read the POH and found the correct spin recovery technique for your aircraft. Then use that technique.

[Pilot DAR]

Take spin training but not before you have read the POH and found the correct spin recovery technique for your aircraft. Then use that technique.

Absolutely. Where a flight manual specifies any procedure or technique for that particular aircraft, that supercedes "blanket" techniques.

During certification, the authority will be evaluating the flight manual, to assure that it provides information which is in harmony with the design requirements.

[moreflaps]

"Take spin training, which should include the appropriate, co-ordinated use of ailerons during recovery."

With respect, I think the physics of the spin suggest otherwise. The spin is due to coupled roll/yaw and is maintained by this couple -coordination of controls at that point are moot. It is a stable state that demonstrably does not respond to aileron control inputs (unless it flattens to the point where rudder is less effective than aileron due to rudder stall/blanketing in which case either pro- or anti-spin may work and you may not know which will reduce the AOA on the more deeply stalled wing which is needed to weaken the roll/spin couple). If there were to be a general method, rather than that stated in the POH, I believe the key is to break the powerful yaw component with neutral aileron (the PARE method not MB). When the yaw stops in PARE the plane is in co-ordinated flight and the rudder used by the pilot to only to stop further yaw i.e. the controls _are_ then automatically co-ordinated because the aileron is already neutral! In PARE the elevator then fixes the stalled wing and the pilot recovers the dive. I think it interesting that if a little excess rudder still exists, it actually helps unstall the more deeply stalled wing (which is good) and is not what coordinated aileron would do. For most pilots, talk of coordinated aileron implies putting aileron and rudder in the same direction which is certainly not what should be advocated for a spin recovery technique IMHO. The PARe method s simple and does not require the pilot to think about establishing coordinated flight which could be hard when disorientation may also be present. If any general technique is to be advocated then the KISS principle is essential and talk about "appropriate" co-ordination is not going to help (the pilot is already sensory overloaded without having to interpret what might be appropriate).

Further, if the pilot has put in a coordinated rudder/aileron control input to stop yaw he worsens the stall on the already more deeply stalled wing which will oppose the rudder input and delay (or even prevent) recovery. I don't think that the idea of inducing opposite yaw by holding in opposite rudder was ever implied in any spin recovery technique, in all the texts I have seen they say when the yaw _stops_ recover by ... (a method that does not add yaw couples)

Cheers

[Final 3 Greens]

Moreflaps

If you come out of the spin and find yourself with nose and one wing down, do you think it is a good idea to recover the normal pitch attitude, before using the aileron to roll wings level?

[Pilot DAR]

Moreflaps,

I'm thinging about what you've presented, though perhaps I am missing some of the intent, as I have no idea what "PARE" means. I have never seen this term in standards, flight manuals, or training texts.

I agree that there are probably reasons of aerodynamics why aileron use may have no benefit in some instances of spin recovery. I do not agree that a pilot is overloaded in having to consider the use of the ailerons during a spin. Rather, I opine that it may be overloading the pilot, to have him/her overcome the instinctive reaction to return to unstalled, co-ordinated flight by "normal" use of the controls.

Many pilots are rudder challenged at the best of times, to now have them concentrate on the use of control which recieves too little attention, to the exlusion of the one they normally use too much, may be overloading.

However, I'll wait to learn about PARE, and keep my mind open....

[Maoraigh1]

I'm just a PPL. I've been taught entry and recovery from spins in Tiger Moth, Chipmunk, C150, C152, and Zlin242L. Each time the instruction was:
Power off. No aileron. Full opposite rudder. Stick progressively forward until spin stops. Centralise controls. Pull out of dive.
I was told the use of aileron to try to lift the more stalled wing would increase the spin forces. I follow the logic of that. Can someone explain the rational for aileron use in simple terms? Both wings are stalled.
P.S. Might it be possible to enter a spin inadvertantly from cruise in turbulence? I'm remembering two NTSB reports of spins.

[Pilot DAR]

the instruction was

Without being disrespectful, was that instruction from the aircraft flight manual? If so, it should be followed. If a pilot chooses a techniqe which is not described in a flight manual, it might be fine, though it still might not be in harmony with the design standards for the aircraft. This also could be okay, I just wonder why not fly the plane the way it was proven to fly for certification.

If the aircraft is in autorotation, one wing has less lift than the other. Both wings still have some lift, just not enough to sustain 1G flight. Generally the outer portions of the wing retain lift longer than the inner portions, into the stall. So if the outer portion of the wing which is providing less lift of the two is still providing some lift, some aileron may provide some more. That small additional lift may help, I've spun types where it did, though only a little.

An interesting exercise when flying an aircraft (which is properly prepared for unusual attitudes and stall practice) is to push the aircraft to between 1G and .5G "over the top", while the airspeed decreases to a little less than the speed commonly associated with a 1G stall. You will find that if you're not demanding the wing lift 1G for a few moments, it will remain unstalled to an even lower airspeed, and the aileons will remain quite responsive. May as well use 'em, unless the flight manual says not to....

[IO540]

If you come out of the spin and find yourself with nose and one wing down, do you think it is a good idea to recover the normal pitch attitude, before using the aileron to roll wings level?(my bold)

AIUI, in a spiral dive recovery you are supposed to level the wings first and only then use the elevator. The reason given is to reduce the stress on the tail section.

So I would guess that once you recover from a spin, and you are going fast enough forward for ailerons to work (i.e. perhaps not the AF447 case ;) ) then levelling the wings could be a good idea, before pulling back out.

However, one variation of the spiral dive recovery involves a recovery from a very "advanced" spiral dive (at/above Vne) where once you level the wings, the speed is too great for the current pitch trim setting and if one did nothing with the pitch, one would overload the wings (+G), so one actually needs to push the yoke forward a bit to limit the +G.

Might it be possible to enter a spin inadvertantly from cruise in turbulence? I'm remembering two NTSB reports of spins. I don't think so unless you are doing stuff which brings you close to Vs in cruise.

One way to do this is to be probing the operating ceiling. In high altitude flight, engine power drops off and IAS keeps reducing. TAS holds up well but eventually IAS reaches Vs... I have come close to the stall a number of times, trying to climb to say FL200 at ISA+something. It's easy to do this wrong with autopilot controlled climbs. Program +300fpm and let it go and it will do it. Throw in uncoordinated flight (lack of elevator input or lack of elevator trim) and some turbulence and a pilot who is dumb (or hypoxic) and you can lose it. I think one SR22 chute pull was after doing that (though surviving pilots have a reason to not say too much).

Another way is to ice up. All bets are off then. You can be flying at 150kt, collect a couple of inches of ice, speeds drops off but actual Vs goes way up, no stall warning because the tab is frozen in the ice, and with some turbulence you can lose it too. I think another SR22 chute pull was after doing that (though surviving pilots have a reason to not say too much).

But I can't see one could do it in say Vs * 1.5 or faster because (on any certified plane) the vertical stabiliser will have tons of authority to limit the yaw caused by turbulence.

But it's a good Q whether turbulence causes roll (with yaw being a secondary effect), or yaw (with roll being a secondary effect). I have noticed that I get a lot of yaw in turbulence, whereas say a 737 (with yaw damping) gets no yaw and very little roll (and just gets a rough up/down ride). Does turbulence really affect one wing more than the other?

[moreflaps]

Hi PDAR, the term PARE is a mnemonic for the NASA recommended general spin recovery technique

Power (to idle)
Aileron (to neutral)
Rudder (full anti-yaw until rotation stops then)
Elevator (check forward to unstall)

After this you should not be spinning, will be unstalled and diving -possibly even in a spiral dive. At this point correct dive recovery is applied (another area which should become second nature during pilot training).

The PARE mnemonic seems to be widely used as far as I know even Wikipedia has a page on it:
http://en.wikipedia.org/wiki/PARE_(aviation)

Cheers

[Pilot DAR]

Interesting. I can't say I completely embrace the PARE, or the article, but as it errs to the conservative side, it's probably useful. Perhaps it's major purpose is to put a memonable "recovery plan" in close reach in the pilot's mind, should a spin occurr. In fairness to most pilots, spins are generally not practiced a lot, so perhaps the recovery techniques become rusty, and the sensations unusual.

Though I spin regularly, I recall spinning a modified Cessna 206. My first recovery was very sloppy, as I did not "assert" my recovery, particularly in pitch. I then recalled having read somewhere in a larger Cessna flight manual, "briskly move the controls forward". When I did this, recovery was prompt and crisp, (though I did get into zero G for a short time). I don't recommend spinning C 206's

I hope for pilots that compotent spin training and occasional practice remain easily available...

[RatherBeFlying]

With incipient spins, the spin entry can be usually arrested with a bit of rudder and relaxation of pitch. In my annual spin checks in gliders, I have to deliberately restrain myself from prompt recovery in the incipient stage as the checker wants to see recovery from a fully developed spin.

After letting the thing go through one turn, I use full opposite rudder, then put the stick forward until I feel the airflow reattaching. It takes a while to develop the feel for this, but 1/4 to 1/3 stick forward from the rear stop seems to do the job. That's in a glider that I'm familiar with.

But in powered a/c, the C/G has more variability and you may very well need to push the stick all the way to the front stop and keep it there.

The C-15x, C-172 and Citabria have straightforward spin recoveries -- and do seem to like a bit more forward stick for a prompt spin recovery.

There is advice out there to simply "let go of everything" and I suspect most a/c (excepting specialised aerobatic types) will recover themselves, but at cost of more altitude loss.

Yes, I believe pilots should experience full spins until they are comfortable with recovery. But it's more important to develop the sense of an incipient spin and be able to stop it then and there. A full spin turning final at 500' usually will hit the ground before recovery.

Remember that the classic fatal stall/spin scenario is a hurried shallow banked turn to final from a tailwind on base with insufficient bank "helped" by rudder.

[Mark1234]

Generally when you're deliberately spinning, ailerons other than neutral is discouraged, unless you're deliberately after a different flavour of spin. As PilotDAR notes, they still do affect things: In general, out spin aileron (stick out) flattens the spin and increases the rate of rotation, similarly in-spin generally slows things down. Of course, that's not necessarily universal.

I confess I'm not entirely sure what co ordinated use in a recovery would look like - out-spin rudder and out aileron would seem a strange thing to do, out spin rudder an in-aileron could have merit - but is hardly co-ordinated.. however, I'm no test pilot.

The PARE (I'd not heard of the acronym, just the steps involved) is about as close to a 'standard' spin recovery as I've seen, certainly by far the most common (POH) recovery of the types I've met. Anecdotally I believe swept wing, (military) type jets prefer an aileron based recovery, don't know why, nor relevant to most of us I'm sure.

If you come out of the spin and find yourself with nose and one wing down, do you think it is a good idea to recover the normal pitch attitude, before using the aileron to roll wings level?

Simple.. always recover to a vertical downline and it doesn't matter ;)

[Pilot DAR]

I'm certainly not a spinning expert, I just know what I'm told to look for

nless you're deliberately after a different flavour of spin.

Not deliberately that, though I stumble into it occasionally. The Caravan was an eye opener, but not in a bad way.

The original certification spin testing for a new aircraft is a huge task, which fortunately, I'm not required to repeat. If my "normal use of the controls" gets me into and out of the spin within the design requirements, everyone is happy. I'm not there to prolong it. None of my projects have been aerobatic aircraft, so the one turn spin is just enough!

I am intrigued with the aileron issue though. I have some test flying with a modified C 172 coming up, so I'll explore the affect of the ailerons a little more while I'm spinning for that project.