Spins, Spiral Dives and Training

I have already been flamed once for bringing up this subject in the
original Parowan accident thread, as being irrelevant to highly
experienced competition pilots!

However for those of them who are not also instructors, that experience
consists of many hundreds or thousands of hours of either flying straight
or circling in thermals! How well would they cope in the event of a sudden
and unexpected upset?

It is important to be able to differentiate between a spin and a spiral
dive because the recovery actions are quite different.

In a spin, the nose will often go well down, despite the fact you are
stalled, the ground will rotate in front of you, and there will be very
little build up of g. The ASI is likely to totally misread due to the
amount of yaw present; it may even go back though zero and show a very
high reading.

In a spiral dive, the nose may remain fairly well up, despite the fact you
are not stalled, and airspeed and g will build up rapidly and continue to
do so. In many ways spiral dives are more dangerous as you risk going
through Vne and breaking up the glider. Spins in themselves are not
dangerous at all, at least as long as you recover before hitting the
deck.

Just a quick reminder of the standard recovery actions:

Spin:

1) Centralise the ailerons
2) Apply full outspin rudder
3) Move the stick steadily and progressively forward until the spin stops
4) Centralise the rudder and ease out of the dive

Spiral dive:

1) Keep the stick fairly well back and use the controls normally to reduce
the angle of bank - a spiral dive is just a very overbanked turn.

IMHO spins and spiral dives should be a part of periodic check flights.

Derek Copeland (UK Gliding Instructor)



At 04:15 04 July 2009, ZZ wrote:
If may, I would like to get off on a bit of a tangent, i.e. the
original subject stated in the title of this thread.

One of the problems that I have observed with students and a few high
time pilots alike is the following: when presented with a spin or a
spiral dive, mis-diagnosing the problem and applying the wrong recovery.

To some who experience these maneuvers infrequently, they appear similar

enough to bring about confusion and as you know, applying the wrong
recovery can get grim.

I believe airspeed, sound and G are the keys with the latter two very
important. Some are so confused by the ground spinning around that they
don't think about looking at the airspeed indicator. But they do seem to

sense if it is relatively quiet or loud and if they are experiencing
more than 1G. A thorough ground briefing on the differences and then
demonstrating both on the same flight really helps. Then follow that
with a lesson where they must make the diagnosis and apply the proper
recovery. This has worked for me. I would enjoy hearing from others who
have thoughts on this very important subject.

Paul
ZZ









8 wrote:
Okay guys, here's your new thread. Please...

Del asks "how well will pilots react if they unexpectedly get into a
spin or a spiral dive? Normally you gird your loins up first before
doing a deliberate spin!"

Answer: this depends on the pilot, of course. By the time you are
gaggle flying, thermaling up off ridges or flying in competition it
damned well better be automatic, reflexive.

The only point to doing deliberate spins by stalling straight ahead
and kicking rudder is to get some sense of how the sailplane behaves
and what it takes to recover from a fully developed spin. It might
also help you develop some sense of spin entry feel, but unintentional
spins normally come from some combination of turning, skidding flight,
gusts, etc. Oh, there's also the famous pilot who transitioned from
15m to std class and early on charged into a gaggle, pulled up,
reached for the "flap" handle and spun out of the gaggle with
spoilers
deployed. UH, hUH! But I won't mention any names :-). I love that
story.

What you should practice is realistic spin entries from thermaling
turns and simulated pattern turns gone bad. Do 'em in all aircraft
configurations. In flapped ships the behavior changes quite a lot.
If you are fooling with CG location, check that out too. Your
responses can and should become fast and accurate. You should do this
until you aren't "girding your loins", you aren't tense. No
panic.
Aircraft departs controlled flight: so what, you deal with it, get it
back.

regards,

Evan Ludeman / T8

On Jul 4, 3:00*am, Derek Copeland wrote:
I have already been flamed once for bringing up this subject in the
original Parowan accident thread, as being irrelevant to highly
experienced competition pilots!

However for those of them who are not also instructors, that experience
consists of many hundreds or thousands of hours of either flying straight
or circling in thermals! How well would they cope in the event of a sudden
and unexpected upset?

It is important to be able to differentiate between a spin and a spiral
dive because the recovery actions are quite different.

In a spin, the nose will often go well down, despite the fact you are
stalled, the ground will rotate in front of you, and there will be very
little build up of g. The ASI is likely to totally misread due to the
amount of yaw present; it may even go back though zero and show a very
high reading.

In a spiral dive, the nose may remain fairly well up, despite the fact you
are not stalled, and airspeed and g will build up rapidly and continue to
do so. *In many ways spiral dives are more dangerous as you risk going
through Vne and breaking up the glider. Spins in themselves are not
dangerous at all, at least as long as you recover before hitting the
deck.

Just a quick reminder of the standard recovery actions:

Spin:

1) Centralise the ailerons
2) Apply full outspin rudder
3) Move the stick steadily and progressively forward until the spin stops
4) Centralise the rudder and ease out of the dive

Spiral dive:

1) Keep the stick fairly well back and use the controls normally to reduce
the angle of bank - a spiral dive is just a very overbanked turn.

IMHO spins and spiral dives should be a part of periodic check flights.

Derek Copeland (UK Gliding Instructor) *

At 04:15 04 July 2009, ZZ wrote:



If *may, I would like to get off on a bit of *a tangent, i.e. the
original subject stated in the title of this thread.

One of the problems that I have observed with students and a few high
time pilots alike is the following: when presented with a spin or a
spiral dive, mis-diagnosing the problem and applying the wrong recovery.
To some who experience these maneuvers infrequently, they appear similar
enough to bring about confusion and as you know, applying the wrong
recovery can get grim.

I believe airspeed, sound and G are the keys with the latter two very
important. Some are so confused by the ground spinning around that they
don't think about looking at the airspeed indicator. But they do seem to
sense if it is relatively quiet or loud and if they are experiencing
more than 1G. A thorough ground briefing on the differences and then
demonstrating both on the same flight really helps. Then follow that
with a lesson where they must make the diagnosis and apply the proper
recovery. This has worked for me. I would enjoy hearing from others who
have thoughts on this very important subject.

Paul
ZZ

8 wrote:
Okay guys, here's your new thread. *Please...

Del asks "how well will pilots react if they unexpectedly get into a
spin or a spiral dive? Normally you gird your loins up first before
doing a deliberate spin!"

Answer: this depends on the pilot, of course. *By the time you are
gaggle flying, thermaling up off ridges or flying in competition it
damned well better be automatic, reflexive.

The only point to doing deliberate spins by stalling straight ahead
and kicking rudder is to get some sense of how the sailplane behaves
and what it takes to recover from a fully developed spin. *It might
also help you develop some sense of spin entry feel, but unintentional
spins normally come from some combination of turning, skidding flight,
gusts, etc. *Oh, there's also the famous pilot who transitioned from
15m to std class and early on charged into a gaggle, pulled up,
reached for the "flap" handle and spun out of the gaggle with
spoilers
deployed. *UH, hUH! *But I won't mention any names :-). *I love that
story.

What you should practice is realistic spin entries from thermaling
turns and simulated pattern turns gone bad. *Do 'em in all aircraft
configurations. *In flapped ships the behavior changes quite a lot.
If you are fooling with CG location, check that out too. *Your
responses can and should become fast and accurate. *You should do this
until you aren't "girding your loins", you aren't tense. *No
panic.
Aircraft departs controlled flight: so what, you deal with it, get it
back.

regards,

Evan Ludeman / T8

This is the "PARE" recovery technique published in the US a by NACA in
1936. However, that publication also stated that this technique was
to be used only in the absence of a manufacturers recommended
recovery method. If such a recommendation exists, it must be used
instead. This remains the position of NACA's successor, NASA.

All Pilots and Operators Handbooks (POH) supplied with certified (And
most experimental) aircraft will have a spin recovery technique
spelled out in the "Emergency" section of the handbook. It is often
at variance to the PARE technique. The handbook may even state that
spins are prohibited indicating that the spin or the recovery from it
is hazardous, even unlikely.

For an excellent source of spin information - and recovery technique
see:
http://en.wikipedia.org/wiki/Spin_%28flight%29

Nevertheless, if you get into an accidental spin, you have to make a
recovery or die, whether or not the aircraft is certified for deliberate
spinning.

The only gliders I know of that may need special recovery techniques are
some large span, flapped gliders such as the Nimbus 4. If you have flaps
the first action should be to select neutral flap if you are already in a
positive setting. This is to avoid exceeding the flap limiting speed in
the recovery dive.

Derek Copeland


At 18:26 04 July 2009, bildan wrote:

This is the "PARE" recovery technique published in the US a by NACA in
1936. However, that publication also stated that this technique was
to be used only in the absence of a manufacturers recommended
recovery method. If such a recommendation exists, it must be used
instead. This remains the position of NACA's successor, NASA.

All Pilots and Operators Handbooks (POH) supplied with certified (And
most experimental) aircraft will have a spin recovery technique
spelled out in the "Emergency" section of the handbook. It is often
at variance to the PARE technique. The handbook may even state that
spins are prohibited indicating that the spin or the recovery from it
is hazardous, even unlikely.

For an excellent source of spin information - and recovery technique
see:
http://en.wikipedia.org/wiki/Spin_%28flight%29

At 19:45 04 July 2009, Derek Copeland wrote:
Nevertheless, if you get into an accidental spin, you have to make a
recovery or die, whether or not the aircraft is certified for deliberate
spinning.

I have to take issue with that statement which nicely illustrates my
point. Knowing any recovery technique is not going to help you at all if
you spin from a low final turn, the only thing that will save you is
recognising what is happening and stopping it happening.

I would go further and say that recovery in such a situation should not be
attempted. If you look at the video you see that the glider hit wingtip
first, which is what wound up the rotational speed, and then the nose
impacted, much of the impact was absorbed by this process and the crew
survived.
If you imagine the situation where the glider is just a little higher and
recovery is attempted and part suceeds, what is the first thing that
stops, the rotation so instead of impacting the ground and having some of
the the impact energy absorbed the glider hits the ground, nose first,
accelerating, known as tent pegging I believe. This is very bad news for
the crew and yet we quite happily consider recovery from spinning of
greater importance than recognition of the early signs and prevention.

Knowing the spin recovery procedure would have been of no use whatsoever
to the crew of the glider in the video.

I am not very experianced or an instructor, but see this video, ...

http://www.youtube.com/watch?v=jvK1ONl1CqE

After being slow to recoginise the cable break, the glider is stalled and
rotating, but the nose does not go down, so the crash is perhaps less
painfull than going in nose first.?

I hope I would have better recoginised/reacted to the break, but if not I
would have still lowered the nose more to unstall the wing and hopefully
flare the landing?????

David.

At 22:45 04 July 2009, Don Johnstone wrote:
At 19:45 04 July 2009, Derek Copeland wrote:
Nevertheless, if you get into an accidental spin, you have to make a
recovery or die, whether or not the aircraft is certified for
deliberate
spinning.

I have to take issue with that statement which nicely illustrates my
point. Knowing any recovery technique is not going to help you at all if
you spin from a low final turn, the only thing that will save you is
recognising what is happening and stopping it happening.

I would go further and say that recovery in such a situation should not
be
attempted. If you look at the video you see that the glider hit wingtip
first, which is what wound up the rotational speed, and then the nose
impacted, much of the impact was absorbed by this process and the crew
survived.
If you imagine the situation where the glider is just a little higher
and
recovery is attempted and part suceeds, what is the first thing that
stops, the rotation so instead of impacting the ground and having some
of
the the impact energy absorbed the glider hits the ground, nose first,
accelerating, known as tent pegging I believe. This is very bad news for
the crew and yet we quite happily consider recovery from spinning of
greater importance than recognition of the early signs and prevention.

Knowing the spin recovery procedure would have been of no use whatsoever
to the crew of the glider in the video.

Don,

The German DG500 pilots escaped serious injury because, being so low, they
didn't have that far to fall when the spin developed. Also DG gliders have
crash resistant cockpits. Even so I bet that hurt!

If you are in a full spin, you are decending at 50-60 knots or
5000ft/min+, which is probably enough to kill you. It certainly killed a
former syndicate partner of mine who spun off a slow autotow launch at
about 800ft and failed to make any sort of recovery. Once in a fully
developed spin it probably matters not if you spin into the ground, or
dive into it. If you have enough height to do so, it is better to recover
because you then stand a very good chance of staying alive.

I have already pointed out that you cannot afford to spin once down to
circuit height, so you have to have to fly accurately at a safe airspeed.


Derek Copeland


At 22:45 04 July 2009, Don Johnstone wrote:
At 19:45 04 July 2009, Derek Copeland wrote:
Nevertheless, if you get into an accidental spin, you have to make a
recovery or die, whether or not the aircraft is certified for
deliberate
spinning.

I have to take issue with that statement which nicely illustrates my
point. Knowing any recovery technique is not going to help you at all if
you spin from a low final turn, the only thing that will save you is
recognising what is happening and stopping it happening.

I would go further and say that recovery in such a situation should not
be
attempted. If you look at the video you see that the glider hit wingtip
first, which is what wound up the rotational speed, and then the nose
impacted, much of the impact was absorbed by this process and the crew
survived.
If you imagine the situation where the glider is just a little higher
and
recovery is attempted and part suceeds, what is the first thing that
stops, the rotation so instead of impacting the ground and having some
of
the the impact energy absorbed the glider hits the ground, nose first,
accelerating, known as tent pegging I believe. This is very bad news for
the crew and yet we quite happily consider recovery from spinning of
greater importance than recognition of the early signs and prevention.

Knowing the spin recovery procedure would have been of no use whatsoever
to the crew of the glider in the video.

bildan wrote:

All Pilots and Operators Handbooks (POH) supplied with certified (And
most experimental) aircraft will have a spin recovery technique
spelled out in the "Emergency" section of the handbook. It is often
at variance to the PARE technique.

All JAR certified gliders, which means all European manufactured gliders
certified after about 1970, *must* recover with the "standard method",
which happens to be the same as what you call "pare". And they must do
so with all allowed loadings, and even with asymmetric water ballast.

On Jul 4, 1:58*pm, John Smith wrote:
bildan wrote:
All Pilots and Operators Handbooks (POH) supplied with certified (And
most experimental) aircraft will have a spin recovery technique
spelled out in the "Emergency" section of the handbook. *It is often
at variance to the PARE technique.

All JAR certified gliders, which means all European manufactured gliders
certified after about 1970, *must* recover with the "standard method",
which happens to be the same as what you call "pare". And they must do
so with all allowed loadings, and even with asymmetric water ballast.

I think the correct JAR 22 is standard recovery UNLESS the
manufacturer specifies an alternative method.

bildan wrote:

I think the correct JAR 22 is standard recovery UNLESS the
manufacturer specifies an alternative method.

Wrong. A glider *must* meet the standard recovery requirement to be
certified. And it must recover with *all* allowed loading distributions
and also with asymmetrical water ballast, and from a fully developed
spin, defined as 5 turns (unless the spin converts to a spiral dive
earlier). (Yes, 5. The FAR only ask for 3 turns.)

Of course, manufactureres may define other recovery procedures which may
work faster, but nevertheless the standard procedure *must* work. (E.g.
the Cap 10 aerobatic airplane recovers much faster with the stick held
fully back.)

JAR 22 also asks that the spin must recover in less than something like
2 turns (I'm not entirely sure). Note that 2 turns will feel extremely
long!!! E.g. the ASK 21 (with tail ballast) usually recovers in less
than half a turn, but in certain circumstances (weight distribution,
moment of recovery in the pitch oscillation rythm) may last up to 2
turns. If you are not aware of this, then it will frighten you to death
and you will tell everybody that the ASK 21 is a potential killer, which
it's not.