Comparitive spin characteristics was Puchacz fatal accident 18 Jan. 2004 at Hus Bos

Z,

If you read the handbook for your K21s, as amended by Schleicher Tech. Note
23 of Jan. 91 (your handbooks have been updated I hope?) you will find
something about the pause, and something about thrusting the stick straight
onto the forward stop.

The amended ASK 21 Flight Manual page 13 reads:

"III.1 RECOVERY FROM SPIN

"According to the standard procedure spinning is terminated as follows:

"1. Apply opposite rudder (i.e. apply rudder against the direction of
rotation of the spin).

"2. Short pause (hold control inputs for about 1/2 spin turn).

"Warning: Disregarding the pause will result in slower recovery!

"3. Release stick (i.e. give in to the pressure of the stick) until the
rotation stops and sound airflow is established again.

"Warning: Full forward stick may retard or even prevent recovery!

"4. Centralise rudder and allow sailplane to dive out.
The altitude loss from the beginning of the recovery until the normal flight
attitude is regained is about 80 meter (260 feet).

"Note: During spins the ASK 21 oscillates in pitch. From a steep nose
down spin recovery according to the standard procedure is up to 1 turn, from
a flat spin less than 1 turn."

On page 15 we find:

"III.4 WING DROPPING

"The sailplane stalls extremely benign. Nevertheless one always has to
face the possibility of wing dropping because of turbulence. In that case
push stick forward immediately and apply opposite rudder against a
noticeable turn _at the same time_ to regain a normal flight attitude. If
the rudder deflection against the turn is forgotten, a spin may occur even
if the stick pressure is released."

There is more on page 25 and 26 (also amended by TN 23), in particular the
effect of different C. of G. positions is discussed.

There is also the question of whether the minimum placard cockpit weights
are actually based on C. of G. position and moments. Frequently the glider
is placarded with a standard minimum weight, usually 70 kg. (154 lbs.); the
true minimum based on moments may be that figure, or much less, the pilot
has no way of knowing which.

Z, how many of the K 21 pilots at your club know all this?

Regards,

Bill.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.

"Z Goudie" wrote in message
...
At 15:30 16 January 2005, Tony Verhulst wrote:


The 'short pause' is not included in this procedure (it wasn't included
in the JAR-22 norm either, at least not in the last version I
downloaded). I called it 'classic', however, because I read it in most
glider pilot training handbooks. The question is:
where does it come from, what is it's purpose, why isn't it included in
the design rules, what will be the difference in the spin behaviour, and
last but not least, how long or short is a 'short' pause?


I was always of the opinion that the 'short pause'
first came about because it was thought that with a
low mounted tailplane (which most aircraft then had)
use of the elevator first could cause turbulence which
would blank the effect of the rudder and thus slow
down or even prevent the yaw correction.

If that was a good reason, with T tails does it matter
a jot?

My first instinct with any sign of sudden departure
is to thrust the stick through the instrument panel
and UNLOAD THE WING (not necessarily to keep it their
until VNE arrives) along with the appropriate rudder
as required.

Generally I find that the spin stops PDQ.