The Puchacz WAS certified to JAR 22. When it was first
imported into the UK I repeated the tests, prior to
the BGA granting it certification. The testing included
five turns spins with the C of G at the manufacturers
aft limit; recovery was normal in well under one turn.

Having said that:

1. I once had a similar experience to the one described,
when flight testing the Grob Twin II for BGA certification.
Earlier spins at mid-range C of G had been typically
Grob - self recovery after less than a turn. I expected
that it would be just possible to hold it in at aft
C of G. In fact the spin started to flatten after
about two turns. I initiated recovery immediately,
it took three turns to recover (I was considering abandoning
the aircraft at that point).

After lots of phone calls to the manufacturer (who
said it had never happened in their testing), we resumed
testing (Cautiously) and approached the aft C of G
in small increments. Eventually we got to the C of
G position at which I had had the problem - the spin
was perfectly normal! So far I was aware, I had used
exactly the same spin entry technique in both cases.
Clearly there must have been some small difference
(ailerons not quite central, or some such) that made
an important difference. Whatever the cause, I couldn't
get it to repeat, all subsequent spins were unremarkable.

Rogue spins can happen, IN ANY TYPE.

2. The Puchacz described may have had some repair,
or equipment change, that moved the C of G further
aft, and this failed to get into the aircraft's records
(appalling, I know, but it has happened).

3. The elevator deflections may have become mis-set,
allowing greater upward deflection, and less downward.
This can happen unintentionally, I don't know how,
but it would very likely produce the result described.


At 01:36 28 January 2004, Geir Raudsandmoen wrote:
If you were within the permitted CoG range, and used
the standard recovery method, the spin behaviour you
described is definitely non-compliant with JAR 22 certification
rules. JAR22.221 states that a sailplane certificated
for intentional spinning must be able to recover from
a fully developed spin (5 turns) within 1 turn after
recovery action is done. This has to be demonstrated
in several loading and control conditions.

Additionally, this paragraph states that it must be
impossible to obtain uncontrollable spins with any
use of the controls.

The Puchacz may not have been certificated to JAR 22,
but possibly to the older OSTIV rules. However, I very
much doubt that this type of behaviour would have been
acceptable under older certification rules, although
the verification/testing requirements might have been
less strict in earlier days.

Geir

At 01:00 28 January 2004, Tim Shea wrote:
I love to spin. It's exciting. I took aerobatic training
with Wayne
Handley and was taught spin recoveries by him.

I have direct experience spinning the Puchacz at Minden.
This is what
I remember from my experience. Your mileage may vary.
With friends (usually lighter than me) in the front,
I spun it while
sitting in the back seat more than a dozen times. The
CG was within
the published range and I didn't have any trouble with
simple
recovery- stick centered and forward and rudder away
from the
direction of rotation. Worked great.
I should mention that I used to be 50 lbs heavier than
I am now, but
still in the published range for the plane.
During the training towards my instructors rating,
I spun the Puch
twice with my instructor. The first 2 or so rotation
spin I was able
to recover normally, no sweat. The second manuver was
quite different.
I was asked to let the spin develop a little deeper
for the second.
After 4 or so rotations, the nose seemed to float up
and the rotation
*seemed* to slow considerably. I remember thinking
that this is cool!
Kind of like floating. When it was time for the recovery
I applied the
control inputs I'd been taught (as specified above)
and much to my
surprise, nothing different happened.....for a long
time. I estimate
that we completed another 5+ rotations nose high before
it broke,
rolled over and recovered. I had the stick centered
and against the
front stop with the rudder also pegged away from the
rotation. We
recovered with several (4 or 5) thousand feet under
us (we'd been
playing at cloudbase at about 15K).
Once on the ground, we discussed this incident in the
grumpy bar for
at least an hour. I (and he) decided to never spin
the Puch again. I
didn't. I doubt he did either.
I had heard of this happening before. I assumed that
it was from
operation outside of the design envelope. Apparently
I was wrong.
John Shelton probably said it best: 'On my own as a
test pilot, I will
certainly get killed'. I felt like a dumb-ass for quite
a while (more
than usual) after that.