Recovering from a FLAT spin.

[Keygrip]

Ok - most prints say it can't be done.

Anybody want to argue with that? What actions would you take to attempt a recovery from a flat spin.

(I wonder what percentage of answers will be smarta:mad:e rather than constructive?)

[Blackshift]

:eek:

Get as much weight forward as you can pronto - slide seats forward and move any items with much weight foward if you can - and hope that this is enough to nudge the nose down towards a conventional spin in time for you to recover normally when (and if!) the flight controls regain their effectiveness.

Could also try applying power with control column fully forward to induce a pitch down I suppose.

That's all I can really think of ... although I suspect that I might also suddenly find religion and pray furiously as a back up plan in such circumstances!

... but only after completing the above actions as best I could.

[VFE]

Could also try applying power with control column fully forward to induce a pitch down I suppose.

So power causes the aircraft to pitch down eh? How's that work then chief? Inverted flat spin.... now you might wanna try the power, I guess?

What would also be of good use here would be to discuss how we avoid the flat spin.

VFE.

[Final 3 Greens]

In retract, I suppose that you could drop the gear.

Who knows what it might do, but it couldn't make things much worse.

[Keygrip]

VFE - you almost made the percentage 50/50 at that point. :E

But - the pitch up with power doesn't happen any more after exercise 4 ('cause we don't let it) - so MAYBE full power, full forward pressure (to prevent nose rising) MIGHT get enough airspeed increase to allow the relevant control surfaces to become effective again?

[FlyingForFun]

Ok - most prints say it can't be done
I've said before on these forums that I don't claim to be particularly knowledgeable about aeros, and that applies here too, so maybe I've got the wrong end of the stick. But when I did my aerobatics training, I entered and recovered from what my instructor called a "flat spin". Basically, enter a normal spin, then add power. The more power you add, the flatter the spin becomes - from the pilots perceptive, the nose was noticeably higher, almost as high as the S+L attitude.

Recovery was the "standard" spin recovery as for a normal spin, including reducing power to idle first (which is part of the normal recovery anyway).

This was in a Great Lakes bi-plane. If my memory serves me correctly, we also did the same thing in a Pitts S2B. And also if my memory serves me correctly, we did this both upright and inverted.

FFF
--------------

[VFE]

It's a fair point Keygrip. Slipstream over rudder might be a possibility but it ain't gonna pitch the nose down. Wouldn't increased power also affect the gryoscopic properties of the spinning aircraft in some way?

Where's your test pilots when ya need 'em eh?!

VFE.

[Say again s l o w l y]

The power helping the spin will also depend on which way the a/c is spinning.

Adding power my help, it certainly won't make it worse! It may give you enough airflow over the rudder and elevators to do something.

I think the key is, if it ain't working with the standard recovery for that machine, then try anything!

[VFE]

Not forgetting that many a good man has been killed "trying anything" during a spin when the aircraft does not respond to the standard recovery action after 3 or more rotations.

They get worried, panic, and try something else.... then it's "hello terror firma" [sic].

VFE.

[greeners]

Sorry guys, but if you want to learn how to do this properly, go to a suitable training organisation that will show you how.

In most GA aircraft a flat spin should be recoverable, given correct technique and enough height.

[Speed Twelve]

I'd reach up, pull the canopy handle, call 'jump, jump, jump' to the stude then unstrap and go over the side with my left hand on the d-ring.

[Blackshift]

.... but not from 10,000ft presumably - c'mon mate give us yer tuppensworth... you know you want to!

[Speed Twelve]

Ok Blackie...

The Firefly will enter a flat-ish high-rotational spin mode if the normal spin recovery is mishandled even slightly. Us chaps are required to do a dual high-rot spin sortie annually in which this spin mode is deliberately induced and the instructor left to sort it out.

Delayed spin recovery is pretty straightforward, reapply pro-spin controls and recommence the normal recovery technique. In a high-rot spin the stick tends to go pretty much all the way to the forward stop. The aircraft snaps out of the spin pretty abruptly and if you aren't circumspect with centralising the control column then an outside loop tends to commence! :D

There are no other published spin recovery drills that we use. Prevention is quite good, and a lot of emphasis is placed on incipient spin recovery technique in the mil. Applying this promptly and correctly will sort things out no matter how wild the initial departure, as long as you are quick and accurate with the controls.

First item on the Immediate Action Drill for a full spin incidentally is 'check height'. If you are approaching your pre-calculated minimum abandonment height (transition level + height of ground) then you'd just throw the aircraft away. At minimum abandon (normally FL35-FL40) there's just enough time to get rid of the sunroof, unstrap, step outside, get clear the aircraft and pull the d-ring. Incidentally, the last time a mil crew had to throw away a Firefly in a spin the instructor had to physically crawl over the side of the cockpit against rotational 'g' before jumping clear AFAIK.

I wouldn't be keen to deliberately spin an aircraft without a parachute. Even C152s can bite. An ex-Perth CFI managed to recover (at 1500' agl IIRC) from a high-rot spin in one a few years back. I think a CAA test pilot became involved with that one.

[LD Max]

I'm generally inclined to agree with Blackshift's original post about getting the weight forward pronto.

Interesting post from Speed Twelve, however, since the principle there is clearly to re-establish a bog-standard (non-flat) spin before implementing the correct recovery. All very sensible really.

However, if we are talking about an unintentional flat spin in something like a PA-28 for example, I would start by saying a Flat spin is defined as "Rate of Yaw exceeding Rate of Roll in any attitude including inverted". Unintentional Flat spins are usually, (I accept not always), caused by an AFT CG.

Flat spins around the CG are considered impossible to recover from, therefore your primary task will be to move the CG forward and initiate or increase Rate of Roll so that it at least equals or exceeds the existing rate of Yaw.

I would suggest a suitable Recovery procedure is Power OFF, (since power tends to flatten a spin), move the CG forward, (seats, bags, POH, Extinguisher, lean forward), while applying PRO SPIN Aileron. I would tend to suggest Neutral on the rudder, because although the secondary effect of the rudder is to induce Roll, clearly one wishes to reduce the dominant yaw without necessarily impeding any roll being commanded by the ailerons.

When, (or if), Rate of Roll equals or exceeds Rate of Yaw, the spin is no longer considered "Flat" and you can then execute a standard spin recovery.

Thing is - if this were a test question - an FAA examiner can't really say any of this is particularly wrong, because INTENTIONAL flat spins are limited to very few aircraft types and the recovery procedure is pretty much as as above, (without considering how to change the CG).

UNINTENTIONAL flat spins, however, require you to be a "test pilot" because the aircraft almost certainly won't be certified for it, since being well outside the utility category is probably what got you into the situation in the first place! So I don't suppose there is a definitive answer. But if it were me, I'd start with the above and work from there.

I have heard of people rocking the aircraft, "pumping" the control column etc etc. Who knows what will work on your type of plane? One only hopes you figure something out in time. If you don't have a parachute, let's hope there's a lake nearby and you might be able to bale out!

[DFC]

It's a fair point Keygrip. Slipstream over rudder might be a possibility but it ain't gonna pitch the nose down. Wouldn't increased power also affect the gryoscopic properties of the spinning aircraft in some way?
Where's your test pilots when ya need 'em eh?!
VFE.

I have flown at least 3 types that pitch down when power is applied. The pitching direction depends on the position of the engine and the thrust line and drag line.

Regards,

DFC

[LD Max]

The pitching direction depends on the position of the engine and the thrust line and drag line.


DFC is, of course, quite correct. However increased slipstream over a bottom mounted elevator (i.e. not a T-tail) is likely to increase elevator authority. Therefore pushing forward on the control column with an increased slipstream will tend to lower the nose (relative to the pilot) on most aircraft.

Of course this also ignores the effect of the CG around which all the moments will rotate. If the CG is too far aft, then no amount of elevator authority will lower the nose, which is probably why an aft CG is cited as the most common reason for entering an inadvertant flat spin.

Any spin can be defined as autorotation in any three axes. Whether it is "flat" or not depends only upon the relationship between Roll and Yaw, since the attitude of the aircraft is immaterial. The trick to getting out of a flat spin is to ensure rate of roll >= to rate of yaw. You can do what you like with pitch! Unless this leads to an increase in the rate of roll, your spin is still flat.

For my money, I could live with a pitch up just as easily as a pitch down upon closing the throttle. A pitch down is likely to enter a normal spin. A pitch up is likely to enter an inverted spin. Both are equally likely to promote roll, and therefore permit a standard spin recovery.

[7gcbc]

Adding power my help, it certainly won't make it worse! It may give you enough airflow over the rudder and elevators to do something.

or in the case of the Pitts S2b adding power will raise the nose , accelerate more, and flatten the spin even further. (which puts you further away again from recovery), it actually depends on the type.

I think Greeners has made the only point worth making.

Sorry guys, but if you want to learn how to do this properly, go to a suitable training organisation that will show you how.
:ok: :ok: :ok:

[Capt Pit Bull]

I have flown at least 3 types that pitch down when power is applied. The pitching direction depends on the position of the engine and the thrust line and drag line.


Point of information.

It is thrust line related to vertical CofG. Very common misconception regarding the drag line. Remember, force couples are a convenient short cut that can be used to quickly determine the effect of two forces when they are equal.

If T <> D then the combined pitching effect could be either way.

If anyone feels the inclination to tell me I'm talking rubbish, please check your basic physics first ;)

pb

[JonWhitehouse]

Not intending to suggest any rubbish, just adding my tuppence worth.If I remember my basic physics you can replace any a force acting from any point by a force acting from any other point plus a moment acting.
The forces do not have to be equal, if they are not you would simply get an additional force acting through the rotation point which would not affect the pitch up (or down) as there is no moment from it.
Thus the pitching moment will not be either way if the forces are not equal, it can be calculated, and as was said, depends on the a/c type.

BTW it would make sense to calculate the effect of combined forces by shifting them to the vertical CG as you said.

Regards
JW

[rmcdonal]

unintentional flat spin in something like a PA-28 Good luck, I find it a bit of an effort to intentionaly get even a wing to drop at the stall, let alone spin.
Me +Airobatics=:yuk:

[djpil]

Let's start with some basic physics of the spin:
http://oea.larc.nasa.gov/PAIS/Concept2Reality/spin_technology.html from NASA
http://www.ozaeros.com/spin/ostivxx.html from Ozaeros
Then some data - not easy to find actual data online for the effect of power so let's start with power off. One of the classic NASA reports for indicating which aeroplanes are best to stay away from is TP 1009.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770026167_1977026167.pdf There are other reports showing the effect of aileron on recovery.
From memory, Birhle did some powered model tests in the early '80's but reports are not available electronically. http://www.bihrle.com/site/bibliography.html
Pitching moments are a lot more complex than a simple thrust or drag multiplied by a moment arm. First of all, there is the effect of the slipstream on flow at the tail. Secondary effects through gyroscopic moments effect spin rate and sideslip which further change the pitching moment per http://www.ozaeros.com/spin/Spinfig4.jpg
Interesting video of NASA's test of the Grumman Trainer showing attempts to recover from a flat spin. http://www.allaboutguppys.com/spin/spin.mpg
Finally, some training videos including the flat spin in an Extra 300.
http://www.fcitraining.com/video.htm
Back to the question: What actions would you take to attempt a recovery from a flat spin.
My answer is qualified by a few assumptions - you're endorsed on spins, in an airplane approved for intentional spinning and loaded within limits. Follow the method in the POH for the type. If that doesn't work its most likely that you messed up so check everything, go back and try again. That requires explanation, better done face to face which is where greeners and 7gcbc came in.

[javelin]

From Flight Unlimited by Eric Muller and Annette Carson - paraphrased.

Throttle closed - most important

Stick back and 'in' to the spin.

Opposite rudder.

When the rotation stops bring the stick central and neutral, recover, take pants to cleaners !

The Muller/Beggs recovery works for nearly all standard aeroplanes and spins and is let go of the stick and rudder, press fully on the rudder pedal that floats toward you, as the rotation stops, catch the stick as it moves from rear left or right to central.

[VFE]

I have flown at least 3 types that pitch down when power is applied. The pitching direction depends on the position of the engine and the thrust line and drag line.
Regards,
DFC
Were these training aircraft? I was assuming a C152 or similar....

VFE.

[djpil]

Flight International mag of 28 October 1078 had an article on Cessna spinning per a Cessna test pilot. Some extracts relevant to this thread:
Hand off recoveries in the 152: "certainly recovered .. after two turns but lost as much height in the process as if it had spun for another four turns before recovering."
Effect of ailerons in the 152: "Even small amounts of aileron deflection into the spin may increase the rotation rate and prolong recovery." i.e aileron into the spin makes this one go flatter.
One of Gene Beggs' articles on spinning noted that the Beggs/Mueller method failed to recover a 150 - he related a discussion he had with Bill Kershner on the subject then confirmed it himself.
Worth repeating - read the POH for the type - spin characteristics differ significantly between one type and another.

[Blackshift]

VFE,

I take it you've managed to control any pitch-up tendencies with the application of full power during stall recoveries in the 152 without too much difficulty?

[galbz]

So power causes the aircraft to pitch down eh? How's that work then chief?
VFE.

Completely agree...! There seems some confusion on where the controls should be positioned - in some aircraft such as the Pitts S2A, forward pressure of the stick can reduce rudder effectiveness and worsen the stall.

People - Keep it simple stupid! :ugh: Throttle back, neutralise stick, full opposite rudder.

[theresalwaysone]

Does anyone know of anybody who has recovered for an un-intentional flat spin?

[lc_aerobatics]

The Muller/Beggs recovery works for nearly all standard aeroplanes and spins and is let go of the stick and rudder, press fully on the rudder pedal that floats toward you, as the rotation stops, catch the stick as it moves from rear left or right to central.[/quote]

It doesn't on S2B.
You have to close the power put IN SPIN AILERON and then opposite rudder and forward stick.
Power and outstpin airleron only flatter and accelerate spins. :=

[rodthesod]

The Muller/Beggs recovery works for nearly all standard aeroplanes and spins and is let go of the stick and rudder, press fully on the rudder pedal that floats toward you, as the rotation stops, catch the stick as it moves from rear left or right to central.

I don't agree with 'letting go' of controls - in some circumstances this will lead to controls hammering against the stops - not good!

In my experience (A2 RAF JP QFI and 2 years of S2As with Rothmans) flat spins were induced by applying power. If an aircraft spins flat without power you shouldn't be spinning it deliberately (and it's definitely not a 'standard aircraft' nor a 'standard spin').

My suggestion for recovery from said flat spin would be:

Close throttle and hold stick neutral
If time permits, let spin stabilise then 'standard' recovery:
Full rudder to oppose the turn (as indicated by the turn needle)*
Pause (approx 2 seconds)
Move stick smoothly forward until rotation stops
Centralise rudder
Recover from dive* If your aerobatic aircraft doesn't have a T&S, it should have - and don't leave it switched off because you're flying VFR. Its most useful attribute is being able to determine the correct rudder to apply whether you're erect or inverted - if you finish up spinning in the down vertical you may not have that ability (without wasting valuable altitude experimenting).

Of course, I agree with Greeners - go to a reputable organisation and get proper training. Also find out, if possible, what idiosyncrasies your particular type has with regard to spinning and recovery (e.g. use of In/Out-spin aileron, Pause or not, etc.).

Regards,
rts

[Touchin' Down]

Is the aircraft heading out to sea????

[precession]

[Quote=lc_aerobatics]It doesn't on S2B.
You have to close the power put IN SPIN AILERON and then opposite rudder and forward stick.
Power and outstpin airleron only flatter and accelerate spins. :=


Beggs works perfectly especially on the S2A and S2B, has done for many years. Upright, inverted, flat, accelerated, the lot.

Excluding competition spins of course, in an unintentional spin this assumes you know which way is up or down, which direction you are spinning and which way the yaw and roll is, and if you are in a true FLAT ( I mean developed accidental flat spin - which was pointed out as to be exceptionally rare), you would have power on and in a pitts the rate of rotation would be be brisk, with inspin (will only lower the nose) or fwd stick incorrectly timed with application of opposite rudder (assuming you pick the correct one) in the "heartbeat" moment, you'd find yourself in a crossover.


Curtis Pitts rarely endorsed anything, however a letter inside the first page of Gene Beggs book "Spins in the Pitts Special" is about as close as you get, and that book teaches the hand's off method.