At 05:48 02 July 2006, wrote:
I am glad the pilot was not more severely injured!

Based on your observations of the wreckage and discussions
with the
pilot and observers, what was the sequence of events
in this accident
and what do you believe caused it?

Mark,

I assume you are the Mark Grubb from Tahachapi so you
probably know this glider. I never visited there and
obviously never flew the Caproni, so you might be able
to shed some light also. I am obviously concerned
about the whole episode and want to ensure I can do
whatever I can to prevent something like this from
happening again.

I was not there at the time, so the following is repeated
from the observers and pilot. The pilot was flying
on the right. As soon as the aircraft was about 5
feet in the air on tow launch, the right wing began
to fold up at the connecting joint. The pilot immediately
released from the tow and the Caproni did a rolling
climb to about 30 feet and then nosed almost straight
down. It hit at the top or side of the cockpit, still
rotating, and ripped off the vertial stablizer. It
continued rotating upright and slid across the runway
into the grass almost completely crushing the right
side of the cockpit. Emergency crews were there within
10 minutes but the pilot was already pulled out by
onlookers and given emergency care. At first he could
not breathe, but was able to before anyone reached
the cockpit.

The previous day was spent conducting tows on a PIK
20 to establish decision points, lift off, and other
parameters prior to flying the same test patterns with
the Caproni as there has not been much glding at the
field for a long time and we wanted to have everything
planned out.

The wing failed for some reason. Visual inspection
on assembly indicated the bottom and top pin were in
place and flush, (actually inset a bit) but I do not
know if that is a failsafe inspection method. The
assembly instructions were followed in a slow and deliberate
manner, this was going to be a draw to bring advanced
flying to the area so we were intent on everything
being done right and looking good. We didn't have anyone
that was really experienced in assembling the Caproni
itself there, although lots of time assembling other
gliders. The pilot had, as mentioned, had videotapes
of assembly and disassembly. I did not watch them,
but read the manual and followed his instructions.

I do remember we had to position the wing twice to
get the pin seated properly. The first time the wing
was not flush, the second time it was tight.

But only three things could have happened.

1. Misassembly
2. Proper assembly but a mechanical design or aging
deficiency prevented full engagement of the pin
3. Mechanical failure

Since the FAA did not talk to me I can only repeat
that the pilot said to me the FAA provided a verbal
summary to him recently. He said he was told that no
evidence of misassembly was found and they believe
a defect allowed the pin to appear to be engaged, but
it may not have been quite in place or fully expanded,
I can't remember the exact conversation. He mentioned
something about a possible AD. I hope to see the formal
NTSB finding soon.

The wing connectors did not look like mechanical failure
or metal fatigue or anything like that. They were not
ripped or torn.

Thoughts?