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