On Jul 1, 2:01*pm, Craig wrote:
On Jul 1, 12:31*pm, "noel.wade" wrote:



I agree. But I am especially bothered by accidents that don't seem to
fall under any of the above critical points.

Ramy

Ramy -

While its too early to talk about accident causation, in both cases
there appears to be some stall/spin behavior in the chain of events.

Stall/spin accidents are a known problem and an area that _all_ pilots
should be aware of. *There is no excuse for not practicing them and/or
taking spin recovery training.

Every pilot should understand their CG (and its effects on stall/spin
behavior of their particular aircraft). *They should also think about
stall/spin behavior and CG changes when they load up on water ballast
as well.

--Noel

Some of our birds are placarded against spinning (my Nimbus 3
included). *Spin training is a must, but something like a Blanik won't
necessarily prepare a pilot for a glider with a less benign spin
mode. *All of our machines "talk" to us in the air. *The best thing we
can do is learn how to really listen to them.

Craig

After many years of first learning spins, practicing them and finally
teaching them, I've developed the opinion that what we do to teach
spins has little to do with the actual killer spin. Who would
inadvertently haul the nose way up then stomp full rudder at the stall
break?

The people who taught me the killer spin were my students. As in, "I
didn't know a glider would do that." It helps to have a easily
spinable glider like a 2-32, Blanik or Lark although the 2-32 tends to
spin too easily.

These spins require a set up. First, fly at minimum controllable
airspeed for at least 30 seconds. Try to let the glider slowly and
smoothly enter "mushing flight". In "mushing flight" the glider is
not quite stalled but the airflow over the wing has become unstable.
Any disturbance will trip it into a full stall. The angle of attack
is very high due to the sink rate - not a nose high attitude. In
fact, the nose can be near the usual gliding attitude.

Any attempt to turn will trip an asymmetric stall which will develop
into a spin in less than a second. Just before the glider spins,
everything "looks" normal. (Except, of course, for the ridiculously
low airspeed, sloppy controls, absence of wind noise etc...) Several
high time glider pilots doing a BFR with me didn't see this one coming
and were visibly shaken by their 'inadvertent spin'.

What happens next is crucial. If the pilot does nothing, the glider
is likely to transition into a spiral dive. If the pilot then applies
spin recovery control inputs the spiral dive will become much worse.
Some of the scariest rides I've had is with a pilot using "anti-spin"
control inputs while in a spiral dive.

In most fatal "spin-in" accidents, I think the glider is likely to
have transitioned to a spiral dive before impact. This can also
explain some in-flight breakups following an inadvertent spin.