Spins, Spiral Dives and Training

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

Derek Copeland wrote:
For those of you who think spins can only be entered from almost
straight flight in a nose height attitude with a bootful of rudder,
have a look at the following video:

http://www.youtube.com/watch?v=_xCct8cDtyk

"This video or group may contain content that is inappropriate for some
users, as flagged by YouTube's user community. To view this video or group,
please verify you are 18 or older by signing in or signing up."

Did it involve a fatality?

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

Jim Logajan wrote:

Did it involve a fatality?

Listen to the text: The pilot suffered only slight injuries.

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.

John Smith wrote:
Jim Logajan wrote:

Did it involve a fatality?

Listen to the text: The pilot suffered only slight injuries.

You elided the essential part where I pointed out that one can't view the
video (and therefore "listen to the text") without first creating an
account on Youtube and atesting that one is 18 or over.

If it didn't involve a fatality, why is the video considered inappropriate
for some viewers?

Jim Logajan wrote:

You elided the essential part where I pointed out that one can't view the

I think this link works for all, it's the same video.
http://www.youtube.com/watch?v=GUyVL...rom=PL&index=2

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.

On Jul 3, 5:45*pm, Don Johnstone wrote:
At 21:31 03 July 2009, John Smith wrote:

Don Johnstone wrote:

with the Junior, and is that problem in fact worse to the extent that
there is no recovery? We cannot know for sure but there is evidence
that
points that way.

Yes, we can and do know. The Puchacz as well as the Junior have been
frequently flown in aerobatics contests. To my knowledge, no Puch nor
Junior has been spun into the ground during a contest. So they do
recover. More, they even do recover forseeably and precisely, otherwise
they wouldn't be flown in contests.

Yes, but are they flown in contests with the CofG aft and in the case of
the Puchacz with the rear seat occupied with a heavier pilot? I doubt it.
I am not saying that under all loading conditions *that there is a
problem. What I am suggesting is that under some loading conditions there
may well be. What has been said in previous posts tends to indicate there
might be.
Evidence from pilots who recover is unhelpful, evidence from pilots who
don't is not available.
My one experience (in a Puchacz) showed me that there was a problem and I
resolved from that day that I would never walk under one let alone fly in
one again. I assume the instructor filed a report, at the time I was not
involved with the BGA at all.

I think the Puchacz spin characteristics are well explained in this
report.
http://www.tsb.gc.ca/eng/rapports-re...4/a05o0204.asp

Note the paragraph where is states that after extensive testing they
found that the only way a recovery could be prevented is by holding
full back stick. It further states that the nose must be pushed to a
very steep nose down attitude, which appears from the cockpit to be
past the vertical, to get reliable recovery. They suggest that failed
spin recoveries likely result from pilots unwilling to push the nose
that far down.

The Puchacz POH can be found he
http://soargbsc.com/members/manuals/puchacz.pdf

It has two pages devoted to spins. It specifies that the ailerons
MUST be held neutral, otherwise oscillations will result. It also
says that with the CG aft of the mid point, the stick has to go
forward of neutral elevator and to expect the spin may continue beyond
one turn after anti- spin controls are applied. It also says rudder
and elevator control forces are high during the spin recovery.

It seems reasonable to say that Puchacz are spun in by pilots who are
unfamiliar with its special spin recovery characteristics - perhaps by
pilots who haven't bothered to read the POH and believe all they have
to know is the "standard spin recovery" technique.

The Puchacz is not a dangerous glider. There may be dangerous pilots
who fly them, however.

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.