Accident in Namibia, SH Ventus 2cxm

In Denmark we had a serious incident regarding an Arcus.

The left wing airbrake bell crank ruptured as a consequence of inadequate weld quality. The strength of the welds was insufficient to withstand airbrake bell crank operational loads. The bell crank broke as the glider was in 600ft and had a speed of 108t. The left airbrake extended, The pilot made a brilliant recovery extending the right airbrake and landed the glider 32 seconds later.

You find the full report http://www.hcl.dk/index.php?option=c...order=&lang=da

-Peter

Uh oh. That's no good. Has an AD for the Arcus been issued yet? Lots of load on those spoilers for sure.

At 17:19 31 January 2016, smfidler wrote:
Uh oh. That's no good. Has an AD for the Arcus been issued yet? Lots
of
load on those spoilers for sure.


The AD for the duo came out June or July we monitored it and changed to the

new stronger one when the annual was done at Christmas (uk)

I was the PIC in the accident involving a Nimbus 4DM in Bitterwasser.
We loose the control of the glider at 3500 meters height and at 110km/h when we wanted to exit a poor left circling thermal.
Why?? I never use the airbrakes. I put the flaps in full negative position and after several spins I tried to stop the dive at very high speed, the two outside wings broke..
We succeed to bail out (less then 15 seconds with the parachute open for me before to reach the ground!)
We spent the afertnoon and the night before the rescue team from Pokweni found us early in the morning.
We wife and me are safe, just spin problems for me.
But I don't know what happends (no water or fuel in the wings).
I hope the investigations will found the reason of this loose of control in a normal flight condition.

I wonder if all the Nimbus 4D crashes were from a spin to the left? I know someone who measured the angle of incident on a Nimbus 4DM and he thought the left wing was off by a few degrees. I have no personal knowledge of how the measurements were taken. I have several hundred hours in a Nimbus 4D and Nimbus 4DM. Have about 500ish hours in a Nimbus 4T. Loved those birds.


On Sunday, January 31, 2016 at 11:49:21 AM UTC-8, wrote:
I was the PIC in the accident involving a Nimbus 4DM in Bitterwasser.
We loose the control of the glider at 3500 meters height and at 110km/h when we wanted to exit a poor left circling thermal.
Why?? I never use the airbrakes. I put the flaps in full negative position and after several spins I tried to stop the dive at very high speed, the two outside wings broke..
We succeed to bail out (less then 15 seconds with the parachute open for me before to reach the ground!)
We spent the afertnoon and the night before the rescue team from Pokweni found us early in the morning.
We wife and me are safe, just spin problems for me.
But I don't know what happends (no water or fuel in the wings).
I hope the investigations will found the reason of this loose of control in a normal flight condition.

I wonder if all the Nimbus 4D crashes were from a spin to the left? Wasn't the Minden crash a spin to the left?



On Sunday, January 31, 2016 at 11:49:21 AM UTC-8, wrote:
I was the PIC in the accident involving a Nimbus 4DM in Bitterwasser.
We loose the control of the glider at 3500 meters height and at 110km/h when we wanted to exit a poor left circling thermal.
Why?? I never use the airbrakes. I put the flaps in full negative position and after several spins I tried to stop the dive at very high speed, the two outside wings broke..
We succeed to bail out (less then 15 seconds with the parachute open for me before to reach the ground!)
We spent the afertnoon and the night before the rescue team from Pokweni found us early in the morning.
We wife and me are safe, just spin problems for me.
But I don't know what happends (no water or fuel in the wings).
I hope the investigations will found the reason of this loose of control in a normal flight condition.

Francois,

Thank you for posting about your accident! Do you remember how long
from the loss of control and at what altitude above ground before you
bailed out? Fifteen seconds under canopy seems very close!

Glad you and your wife are OK!

Dan

On 1/31/2016 12:49 PM, wrote:
I was the PIC in the accident involving a Nimbus 4DM in Bitterwasser.
We loose the control of the glider at 3500 meters height and at 110km/h when we wanted to exit a poor left circling thermal.
Why?? I never use the airbrakes. I put the flaps in full negative position and after several spins I tried to stop the dive at very high speed, the two outside wings broke..
We succeed to bail out (less then 15 seconds with the parachute open for me before to reach the ground!)
We spent the afertnoon and the night before the rescue team from Pokweni found us early in the morning.
We wife and me are safe, just spin problems for me.
But I don't know what happends (no water or fuel in the wings).
I hope the investigations will found the reason of this loose of control in a normal flight condition.



--
Dan, 5J

At the beginning,at about 3500 meters, when we loose the control of the glider at 110/120 km/h, it was like a flat spin, and it seemed impossible to put the rudder on the right.
After several turns with no success for recovery I put the glider in left classical spin, to a last chance maneuver...
When we exit the spin after several turns we were approximately at 500 meters but with a very high speed, and during the rise the two outside wings went off.
We loose almost 1800 meters (ground about 1200 meters)
François

On Sunday, 31 January 2016 17:19:59 UTC, smfidler wrote:
Uh oh. That's no good. Has an AD for the Arcus been issued yet? Lots of load on those spoilers for sure.

For the Arcus, there was a June AD for the inspection of the airbrake bell crank. For my Arcus, the UK agent Southern Sailplanes said the bell cranks were fine when they carried out the inspection.

By the way, there is a Google Group for Arcus operators at https://groups.google.com/forum/#!fo...pp-hirth-arcus

It would be interesting to know if the root cause is the same. If there are a loss of control, and the root cause is unintended opening of airbrakes in flight.

In France there have been a series of incidents with unintended opening of airbrakes at speeds above 130 km/h.

http://www.volavoile.net/index.php?showtopic=10981

Peter


Den søndag den 31. januar 2016 kl. 11.48.10 UTC+1 skrev :
In Denmark we had a serious incident regarding an Arcus.

The left wing airbrake bell crank ruptured as a consequence of inadequate weld quality. The strength of the welds was insufficient to withstand airbrake bell crank operational loads. The bell crank broke as the glider was in 600ft and had a speed of 108t. The left airbrake extended, The pilot made a brilliant recovery extending the right airbrake and landed the glider 32 seconds later.

You find the full report http://www.hcl.dk/index.php?option=c...order=&lang=da

-Peter